Merge pull request #238154 from amjoseph-nixpkgs/pr/gcc/crossStageStatic

gccCrossStageStatic: enable dynamic libraries, rename it

lib/systems/default.nix

@@ -86,7 +86,7 @@ rec {
         # choice.
         else                                     "bfd";
       extensions = rec {
-        sharedLibrary =
+        sharedLibrary = assert final.hasSharedLibraries;
           /**/ if final.isDarwin  then ".dylib"
           else if final.isWindows then ".dll"
           else                         ".so";
@@ -132,6 +132,25 @@ rec {
          # uname -r
          release = null;
       };
+
+      # It is important that hasSharedLibraries==false when the platform has no
+      # dynamic library loader.  Various tools (including the gcc build system)
+      # have knowledge of which platforms are incapable of dynamic linking, and
+      # will still build on/for those platforms with --enable-shared, but simply
+      # omit any `.so` build products such as libgcc_s.so.  When that happens,
+      # it causes hard-to-troubleshoot build failures.
+      hasSharedLibraries = with final;
+        (isAndroid || isGnu || isMusl                                  # Linux (allows multiple libcs)
+         || isDarwin || isSunOS || isOpenBSD || isFreeBSD || isNetBSD  # BSDs
+         || isCygwin || isMinGW                                        # Windows
+        ) && !isStatic;
+
+      # The difference between `isStatic` and `hasSharedLibraries` is mainly the
+      # addition of the `staticMarker` (see make-derivation.nix).  Some
+      # platforms, like embedded machines without a libc (e.g. arm-none-eabi)
+      # don't support dynamic linking, but don't get the `staticMarker`.
+      # `pkgsStatic` sets `isStatic=true`, so `pkgsStatic.hostPlatform` always
+      # has the `staticMarker`.
       isStatic = final.isWasm || final.isRedox;
 
       # Just a guess, based on `system`

pkgs/development/compilers/gcc/10/default.nix

@@ -9,8 +9,8 @@
 , profiledCompiler ? false
 , langJit ? false
 , staticCompiler ? false
-, enableShared ? !stdenv.targetPlatform.isStatic
-, enableLTO ? !stdenv.hostPlatform.isStatic
+, enableShared ? stdenv.targetPlatform.hasSharedLibraries
+, enableLTO ? stdenv.hostPlatform.hasSharedLibraries
 , texinfo ? null
 , perl ? null # optional, for texi2pod (then pod2man)
 , gmp, mpfr, libmpc, gettext, which, patchelf, binutils
@@ -22,7 +22,7 @@
 , name ? "gcc"
 , libcCross ? null
 , threadsCross ? null # for MinGW
-, crossStageStatic ? false
+, withoutTargetLibc ? false
 , gnused ? null
 , cloog ? null # unused; just for compat with gcc4, as we override the parameter on some places
 , buildPackages
@@ -69,7 +69,7 @@ let majorVersion = "10";
       ++ optional (targetPlatform.libc == "musl" && targetPlatform.isPower) ../ppc-musl.patch
 
       # Obtain latest patch with ../update-mcfgthread-patches.sh
-      ++ optional (!crossStageStatic && targetPlatform.isMinGW && threadsCross.model == "mcf") ./Added-mcf-thread-model-support-from-mcfgthread.patch
+      ++ optional (!withoutTargetLibc && targetPlatform.isMinGW && threadsCross.model == "mcf") ./Added-mcf-thread-model-support-from-mcfgthread.patch
 
       ++ optional (buildPlatform.system == "aarch64-darwin" && targetPlatform != buildPlatform) (fetchpatch {
         url = "https://raw.githubusercontent.com/richard-vd/musl-cross-make/5e9e87f06fc3220e102c29d3413fbbffa456fcd6/patches/gcc-${version}/0008-darwin-aarch64-self-host-driver.patch";
@@ -78,7 +78,7 @@ let majorVersion = "10";
 
     /* Cross-gcc settings (build == host != target) */
     crossMingw = targetPlatform != hostPlatform && targetPlatform.libc == "msvcrt";
-    stageNameAddon = if crossStageStatic then "stage-static" else "stage-final";
+    stageNameAddon = if withoutTargetLibc then "stage-static" else "stage-final";
     crossNameAddon = optionalString (targetPlatform != hostPlatform) "${targetPlatform.config}-${stageNameAddon}-";
 
     callFile = lib.callPackageWith {
@@ -99,7 +99,7 @@ let majorVersion = "10";
         binutils
         buildPackages
         cloog
-        crossStageStatic
+        withoutTargetLibc
         enableLTO
         enableMultilib
         enablePlugin
@@ -214,7 +214,10 @@ lib.pipe (stdenv.mkDerivation ({
             )
           '';
 
-  inherit noSysDirs staticCompiler crossStageStatic
+  # kludge to prevent a mass-rebuild; will be removed in a PR sent to staging
+  crossStageStatic = withoutTargetLibc;
+
+  inherit noSysDirs staticCompiler
     libcCross crossMingw;
 
   inherit (callFile ../common/dependencies.nix { })
@@ -295,5 +298,5 @@ lib.pipe (stdenv.mkDerivation ({
 // optionalAttrs (enableMultilib) { dontMoveLib64 = true; }
 ))
 [
-  (callPackage ../common/libgcc.nix   { inherit version langC langCC langJit targetPlatform hostPlatform crossStageStatic; })
+  (callPackage ../common/libgcc.nix   { inherit version langC langCC langJit targetPlatform hostPlatform withoutTargetLibc enableShared; })
 ]

pkgs/development/compilers/gcc/11/default.nix

@@ -9,8 +9,8 @@
 , profiledCompiler ? false
 , langJit ? false
 , staticCompiler ? false
-, enableShared ? !stdenv.targetPlatform.isStatic
-, enableLTO ? !stdenv.hostPlatform.isStatic
+, enableShared ? stdenv.targetPlatform.hasSharedLibraries
+, enableLTO ? stdenv.hostPlatform.hasSharedLibraries
 , texinfo ? null
 , perl ? null # optional, for texi2pod (then pod2man)
 , gmp, mpfr, libmpc, gettext, which, patchelf, binutils
@@ -22,7 +22,7 @@
 , name ? "gcc"
 , libcCross ? null
 , threadsCross ? null # for MinGW
-, crossStageStatic ? false
+, withoutTargetLibc ? false
 , gnused ? null
 , cloog # unused; just for compat with gcc4, as we override the parameter on some places
 , buildPackages
@@ -82,14 +82,14 @@ let majorVersion = "11";
       ++ optional (stdenv.isDarwin && targetPlatform.isAvr) ./avr-gcc-11.3-darwin.patch
 
       # Obtain latest patch with ../update-mcfgthread-patches.sh
-      ++ optional (!crossStageStatic && targetPlatform.isMinGW && threadsCross.model == "mcf") ./Added-mcf-thread-model-support-from-mcfgthread.patch
+      ++ optional (!withoutTargetLibc && targetPlatform.isMinGW && threadsCross.model == "mcf") ./Added-mcf-thread-model-support-from-mcfgthread.patch
 
       # openjdk build fails without this on -march=opteron; is upstream in gcc12
       ++ [ ./gcc-issue-103910.patch ];
 
     /* Cross-gcc settings (build == host != target) */
     crossMingw = targetPlatform != hostPlatform && targetPlatform.libc == "msvcrt";
-    stageNameAddon = if crossStageStatic then "stage-static" else "stage-final";
+    stageNameAddon = if withoutTargetLibc then "stage-static" else "stage-final";
     crossNameAddon = optionalString (targetPlatform != hostPlatform) "${targetPlatform.config}-${stageNameAddon}-";
 
     callFile = lib.callPackageWith {
@@ -110,7 +110,7 @@ let majorVersion = "11";
         binutils
         buildPackages
         cloog
-        crossStageStatic
+        withoutTargetLibc
         enableLTO
         enableMultilib
         enablePlugin
@@ -227,7 +227,10 @@ lib.pipe (stdenv.mkDerivation ({
             )
           '';
 
-  inherit noSysDirs staticCompiler crossStageStatic
+  # kludge to prevent a mass-rebuild; will be removed in a PR sent to staging
+  crossStageStatic = withoutTargetLibc;
+
+  inherit noSysDirs staticCompiler
     libcCross crossMingw;
 
   inherit (callFile ../common/dependencies.nix { })
@@ -307,6 +310,6 @@ lib.pipe (stdenv.mkDerivation ({
 // optionalAttrs (enableMultilib) { dontMoveLib64 = true; }
 ))
 [
-  (callPackage ../common/libgcc.nix   { inherit version langC langCC langJit targetPlatform hostPlatform crossStageStatic; })
+  (callPackage ../common/libgcc.nix   { inherit version langC langCC langJit targetPlatform hostPlatform withoutTargetLibc enableShared; })
   (callPackage ../common/checksum.nix { inherit langC langCC; })
 ]

pkgs/development/compilers/gcc/12/default.nix

@@ -9,8 +9,8 @@
 , profiledCompiler ? false
 , langJit ? false
 , staticCompiler ? false
-, enableShared ? !stdenv.targetPlatform.isStatic
-, enableLTO ? !stdenv.hostPlatform.isStatic
+, enableShared ? stdenv.targetPlatform.hasSharedLibraries
+, enableLTO ? stdenv.hostPlatform.hasSharedLibraries
 , texinfo ? null
 , perl ? null # optional, for texi2pod (then pod2man)
 , gmp, mpfr, libmpc, gettext, which, patchelf, binutils
@@ -23,7 +23,7 @@
 , name ? "gcc"
 , libcCross ? null
 , threadsCross ? null # for MinGW
-, crossStageStatic ? false
+, withoutTargetLibc ? false
 , gnused ? null
 , cloog # unused; just for compat with gcc4, as we override the parameter on some places
 , buildPackages
@@ -127,11 +127,11 @@ let majorVersion = "12";
       ++ optional (stdenv.isDarwin && langAda) ../gnat-darwin-dylib-install-name.patch
 
       # Obtain latest patch with ../update-mcfgthread-patches.sh
-      ++ optional (!crossStageStatic && targetPlatform.isMinGW && threadsCross.model == "mcf") ./Added-mcf-thread-model-support-from-mcfgthread.patch;
+      ++ optional (!withoutTargetLibc && targetPlatform.isMinGW && threadsCross.model == "mcf") ./Added-mcf-thread-model-support-from-mcfgthread.patch;
 
     /* Cross-gcc settings (build == host != target) */
     crossMingw = targetPlatform != hostPlatform && targetPlatform.libc == "msvcrt";
-    stageNameAddon = if crossStageStatic then "stage-static" else "stage-final";
+    stageNameAddon = if withoutTargetLibc then "stage-static" else "stage-final";
     crossNameAddon = optionalString (targetPlatform != hostPlatform) "${targetPlatform.config}-${stageNameAddon}-";
 
     callFile = lib.callPackageWith {
@@ -152,7 +152,7 @@ let majorVersion = "12";
         binutils
         buildPackages
         cloog
-        crossStageStatic
+        withoutTargetLibc
         disableBootstrap
         disableGdbPlugin
         enableLTO
@@ -271,7 +271,10 @@ lib.pipe (stdenv.mkDerivation ({
             )
           '';
 
-  inherit noSysDirs staticCompiler crossStageStatic
+  # kludge to prevent a mass-rebuild; will be removed in a PR sent to staging
+  crossStageStatic = withoutTargetLibc;
+
+  inherit noSysDirs staticCompiler
     libcCross crossMingw;
 
   inherit (callFile ../common/dependencies.nix { }) depsBuildBuild nativeBuildInputs depsBuildTarget buildInputs depsTargetTarget;
@@ -353,7 +356,7 @@ lib.pipe (stdenv.mkDerivation ({
 // optionalAttrs (enableMultilib) { dontMoveLib64 = true; }
 ))
 [
-  (callPackage ../common/libgcc.nix   { inherit version langC langCC langJit targetPlatform hostPlatform crossStageStatic; })
+  (callPackage ../common/libgcc.nix   { inherit version langC langCC langJit targetPlatform hostPlatform withoutTargetLibc enableShared; })
   (callPackage ../common/checksum.nix { inherit langC langCC; })
 ]
 

pkgs/development/compilers/gcc/13/default.nix

@@ -9,8 +9,8 @@
 , profiledCompiler ? false
 , langJit ? false
 , staticCompiler ? false
-, enableShared ? !stdenv.targetPlatform.isStatic
-, enableLTO ? !stdenv.hostPlatform.isStatic
+, enableShared ? stdenv.targetPlatform.hasSharedLibraries
+, enableLTO ? stdenv.hostPlatform.hasSharedLibraries
 , texinfo ? null
 , perl ? null # optional, for texi2pod (then pod2man)
 , gmp, mpfr, libmpc, gettext, which, patchelf, binutils
@@ -23,7 +23,7 @@
 , name ? "gcc"
 , libcCross ? null
 , threadsCross ? null # for MinGW
-, crossStageStatic ? false
+, withoutTargetLibc ? false
 , gnused ? null
 , cloog # unused; just for compat with gcc4, as we override the parameter on some places
 , buildPackages
@@ -125,7 +125,7 @@ let majorVersion = "13";
 
     /* Cross-gcc settings (build == host != target) */
     crossMingw = targetPlatform != hostPlatform && targetPlatform.libc == "msvcrt";
-    stageNameAddon = if crossStageStatic then "stage-static" else "stage-final";
+    stageNameAddon = if withoutTargetLibc then "stage-static" else "stage-final";
     crossNameAddon = optionalString (targetPlatform != hostPlatform) "${targetPlatform.config}-${stageNameAddon}-";
 
     callFile = lib.callPackageWith {
@@ -146,7 +146,7 @@ let majorVersion = "13";
         binutils
         buildPackages
         cloog
-        crossStageStatic
+        withoutTargetLibc
         disableBootstrap
         disableGdbPlugin
         enableLTO
@@ -265,7 +265,10 @@ lib.pipe (stdenv.mkDerivation ({
             )
           '';
 
-  inherit noSysDirs staticCompiler crossStageStatic
+  # kludge to prevent a mass-rebuild; will be removed in a PR sent to staging
+  crossStageStatic = withoutTargetLibc;
+
+  inherit noSysDirs staticCompiler
     libcCross crossMingw;
 
   inherit (callFile ../common/dependencies.nix { }) depsBuildBuild nativeBuildInputs depsBuildTarget buildInputs depsTargetTarget;
@@ -347,7 +350,7 @@ lib.pipe (stdenv.mkDerivation ({
 // optionalAttrs (enableMultilib) { dontMoveLib64 = true; }
 ))
 [
-  (callPackage ../common/libgcc.nix   { inherit version langC langCC langJit targetPlatform hostPlatform crossStageStatic; })
+  (callPackage ../common/libgcc.nix   { inherit version langC langCC langJit targetPlatform hostPlatform withoutTargetLibc enableShared; })
   (callPackage ../common/checksum.nix { inherit langC langCC; })
 ]
 

pkgs/development/compilers/gcc/4.8/default.nix

@@ -8,8 +8,8 @@
 , profiledCompiler ? false
 , langJit ? false
 , staticCompiler ? false
-, enableShared ? !stdenv.targetPlatform.isStatic
-, enableLTO ? !stdenv.hostPlatform.isStatic
+, enableShared ? stdenv.targetPlatform.hasSharedLibraries
+, enableLTO ? stdenv.hostPlatform.hasSharedLibraries
 , texinfo ? null
 , perl ? null # optional, for texi2pod (then pod2man); required for Java
 , gmp, mpfr, libmpc, gettext, which, patchelf, binutils
@@ -26,7 +26,7 @@
 , name ? "gcc"
 , libcCross ? null
 , threadsCross ? null # for MinGW
-, crossStageStatic ? false
+, withoutTargetLibc ? false
 , gnused ? null
 , buildPackages
 , callPackage
@@ -109,7 +109,7 @@ let majorVersion = "4";
 
     /* Cross-gcc settings (build == host != target) */
     crossMingw = targetPlatform != hostPlatform && targetPlatform.libc == "msvcrt";
-    stageNameAddon = if crossStageStatic then "stage-static" else "stage-final";
+    stageNameAddon = if withoutTargetLibc then "stage-static" else "stage-final";
     crossNameAddon = optionalString (targetPlatform != hostPlatform) "${targetPlatform.config}-${stageNameAddon}-";
 
     callFile = lib.callPackageWith {
@@ -135,7 +135,7 @@ let majorVersion = "4";
         boehmgc
         buildPackages
         cloog
-        crossStageStatic
+        withoutTargetLibc
         enableLTO
         enableMultilib
         enablePlugin
@@ -232,7 +232,10 @@ lib.pipe (stdenv.mkDerivation ({
         ''
     else null;
 
-  inherit noSysDirs staticCompiler langJava crossStageStatic
+  # kludge to prevent a mass-rebuild; will be removed in a PR sent to staging
+  crossStageStatic = withoutTargetLibc;
+
+  inherit noSysDirs staticCompiler langJava
     libcCross crossMingw;
 
   inherit (callFile ../common/dependencies.nix { })
@@ -323,5 +326,5 @@ lib.pipe (stdenv.mkDerivation ({
 // optionalAttrs (enableMultilib) { dontMoveLib64 = true; }
 ))
 [
-  (callPackage ../common/libgcc.nix   { inherit version langC langCC langJit targetPlatform hostPlatform crossStageStatic; })
+  (callPackage ../common/libgcc.nix   { inherit version langC langCC langJit targetPlatform hostPlatform withoutTargetLibc enableShared; })
 ]

pkgs/development/compilers/gcc/4.9/default.nix

@@ -8,8 +8,8 @@
 , profiledCompiler ? false
 , langJit ? false
 , staticCompiler ? false
-, enableShared ? !stdenv.targetPlatform.isStatic
-, enableLTO ? !stdenv.hostPlatform.isStatic
+, enableShared ? stdenv.targetPlatform.hasSharedLibraries
+, enableLTO ? stdenv.hostPlatform.hasSharedLibraries
 , texinfo ? null
 , perl ? null # optional, for texi2pod (then pod2man); required for Java
 , gmp, mpfr, libmpc, gettext, which, patchelf, binutils
@@ -26,7 +26,7 @@
 , name ? "gcc"
 , libcCross ? null
 , threadsCross ? null # for MinGW
-, crossStageStatic ? false
+, withoutTargetLibc ? false
 , gnused ? null
 , buildPackages
 , callPackage
@@ -126,7 +126,7 @@ let majorVersion = "4";
 
     /* Cross-gcc settings (build == host != target) */
     crossMingw = targetPlatform != hostPlatform && targetPlatform.libc == "msvcrt";
-    stageNameAddon = if crossStageStatic then "stage-static" else "stage-final";
+    stageNameAddon = if withoutTargetLibc then "stage-static" else "stage-final";
     crossNameAddon = optionalString (targetPlatform != hostPlatform) "${targetPlatform.config}-${stageNameAddon}-";
 
     callFile = lib.callPackageWith {
@@ -152,7 +152,7 @@ let majorVersion = "4";
         boehmgc
         buildPackages
         cloog
-        crossStageStatic
+        withoutTargetLibc
         enableLTO
         enableMultilib
         enablePlugin
@@ -253,7 +253,10 @@ lib.pipe (stdenv.mkDerivation ({
         ''
     else null;
 
-  inherit noSysDirs staticCompiler langJava crossStageStatic
+  # kludge to prevent a mass-rebuild; will be removed in a PR sent to staging
+  crossStageStatic = withoutTargetLibc;
+
+  inherit noSysDirs staticCompiler langJava
     libcCross crossMingw;
 
   inherit (callFile ../common/dependencies.nix { })
@@ -350,5 +353,5 @@ lib.pipe (stdenv.mkDerivation ({
      '';}
 ))
 [
-  (callPackage ../common/libgcc.nix   { inherit version langC langCC langJit targetPlatform hostPlatform crossStageStatic; })
+  (callPackage ../common/libgcc.nix   { inherit version langC langCC langJit targetPlatform hostPlatform withoutTargetLibc enableShared; })
 ]

pkgs/development/compilers/gcc/6/default.nix

@@ -9,8 +9,8 @@
 , profiledCompiler ? false
 , langJit ? false
 , staticCompiler ? false
-, enableShared ? !stdenv.targetPlatform.isStatic
-, enableLTO ? !stdenv.hostPlatform.isStatic
+, enableShared ? stdenv.targetPlatform.hasSharedLibraries
+, enableLTO ? stdenv.hostPlatform.hasSharedLibraries
 , texinfo ? null
 , flex
 , perl ? null # optional, for texi2pod (then pod2man); required for Java
@@ -29,7 +29,7 @@
 , name ? "gcc"
 , libcCross ? null
 , threadsCross ? null # for MinGW
-, crossStageStatic ? false
+, withoutTargetLibc ? false
 , gnused ? null
 , cloog ? null # unused; just for compat with gcc4, as we override the parameter on some places
 , buildPackages
@@ -78,7 +78,7 @@ let majorVersion = "6";
       ++ optional langGo ./gogcc-workaround-glibc-2.36.patch
 
       # Obtain latest patch with ../update-mcfgthread-patches.sh
-      ++ optional (!crossStageStatic && targetPlatform.isMinGW && threadsCross.model == "mcf") ./Added-mcf-thread-model-support-from-mcfgthread.patch
+      ++ optional (!withoutTargetLibc && targetPlatform.isMinGW && threadsCross.model == "mcf") ./Added-mcf-thread-model-support-from-mcfgthread.patch
       ++ optional (targetPlatform.libc == "musl" && targetPlatform.isx86_32) (fetchpatch {
         url = "https://git.alpinelinux.org/aports/plain/main/gcc/gcc-6.1-musl-libssp.patch?id=5e4b96e23871ee28ef593b439f8c07ca7c7eb5bb";
         sha256 = "1jf1ciz4gr49lwyh8knfhw6l5gvfkwzjy90m7qiwkcbsf4a3fqn2";
@@ -111,7 +111,7 @@ let majorVersion = "6";
 
     /* Cross-gcc settings (build == host != target) */
     crossMingw = targetPlatform != hostPlatform && targetPlatform.libc == "msvcrt";
-    stageNameAddon = if crossStageStatic then "stage-static" else "stage-final";
+    stageNameAddon = if withoutTargetLibc then "stage-static" else "stage-final";
     crossNameAddon = optionalString (targetPlatform != hostPlatform) "${targetPlatform.config}-${stageNameAddon}-";
 
     callFile = lib.callPackageWith {
@@ -137,7 +137,7 @@ let majorVersion = "6";
         boehmgc
         buildPackages
         cloog
-        crossStageStatic
+        withoutTargetLibc
         enableLTO
         enableMultilib
         enablePlugin
@@ -269,7 +269,10 @@ lib.pipe (stdenv.mkDerivation ({
         ))
     );
 
-  inherit noSysDirs staticCompiler langJava crossStageStatic
+  # kludge to prevent a mass-rebuild; will be removed in a PR sent to staging
+  crossStageStatic = withoutTargetLibc;
+
+  inherit noSysDirs staticCompiler langJava
     libcCross crossMingw;
 
   inherit (callFile ../common/dependencies.nix { })
@@ -368,5 +371,5 @@ lib.pipe (stdenv.mkDerivation ({
      '';}
 ))
 [
-  (callPackage ../common/libgcc.nix   { inherit version langC langCC langJit targetPlatform hostPlatform crossStageStatic; })
+  (callPackage ../common/libgcc.nix   { inherit version langC langCC langJit targetPlatform hostPlatform withoutTargetLibc enableShared; })
 ]

pkgs/development/compilers/gcc/7/default.nix

@@ -7,8 +7,8 @@
 , profiledCompiler ? false
 , langJit ? false
 , staticCompiler ? false
-, enableShared ? !stdenv.targetPlatform.isStatic
-, enableLTO ? !stdenv.hostPlatform.isStatic
+, enableShared ? stdenv.targetPlatform.hasSharedLibraries
+, enableLTO ? stdenv.hostPlatform.hasSharedLibraries
 , texinfo ? null
 , perl ? null # optional, for texi2pod (then pod2man)
 , gmp, mpfr, libmpc, gettext, which, patchelf, binutils
@@ -19,7 +19,7 @@
 , name ? "gcc"
 , libcCross ? null
 , threadsCross ? null # for MinGW
-, crossStageStatic ? false
+, withoutTargetLibc ? false
 , gnused ? null
 , cloog ? null # unused; just for compat with gcc4, as we override the parameter on some places
 , buildPackages
@@ -81,13 +81,13 @@ let majorVersion = "7";
       ++ optional (targetPlatform.libc == "musl") ../libgomp-dont-force-initial-exec.patch
 
       # Obtain latest patch with ../update-mcfgthread-patches.sh
-      ++ optional (!crossStageStatic && targetPlatform.isMinGW && threadsCross.model == "mcf") ./Added-mcf-thread-model-support-from-mcfgthread.patch
+      ++ optional (!withoutTargetLibc && targetPlatform.isMinGW && threadsCross.model == "mcf") ./Added-mcf-thread-model-support-from-mcfgthread.patch
 
       ++ [ ../libsanitizer-no-cyclades-9.patch ];
 
     /* Cross-gcc settings (build == host != target) */
     crossMingw = targetPlatform != hostPlatform && targetPlatform.libc == "msvcrt";
-    stageNameAddon = if crossStageStatic then "stage-static" else "stage-final";
+    stageNameAddon = if withoutTargetLibc then "stage-static" else "stage-final";
     crossNameAddon = optionalString (targetPlatform != hostPlatform) "${targetPlatform.config}-${stageNameAddon}-";
 
     callFile = lib.callPackageWith {
@@ -108,7 +108,7 @@ let majorVersion = "7";
         binutils
         buildPackages
         cloog
-        crossStageStatic
+        withoutTargetLibc
         enableLTO
         enableMultilib
         enablePlugin
@@ -218,7 +218,10 @@ lib.pipe (stdenv.mkDerivation ({
         )
       '';
 
-  inherit noSysDirs staticCompiler crossStageStatic
+  # kludge to prevent a mass-rebuild; will be removed in a PR sent to staging
+  crossStageStatic = withoutTargetLibc;
+
+  inherit noSysDirs staticCompiler
     libcCross crossMingw;
 
   inherit (callFile ../common/dependencies.nix { })
@@ -302,5 +305,5 @@ lib.pipe (stdenv.mkDerivation ({
 // optionalAttrs (enableMultilib) { dontMoveLib64 = true; }
 ))
 [
-  (callPackage ../common/libgcc.nix   { inherit version langC langCC langJit targetPlatform hostPlatform crossStageStatic; })
+  (callPackage ../common/libgcc.nix   { inherit version langC langCC langJit targetPlatform hostPlatform withoutTargetLibc enableShared; })
 ]

pkgs/development/compilers/gcc/8/default.nix

@@ -7,8 +7,8 @@
 , profiledCompiler ? false
 , langJit ? false
 , staticCompiler ? false
-, enableShared ? !stdenv.targetPlatform.isStatic
-, enableLTO ? !stdenv.hostPlatform.isStatic
+, enableShared ? stdenv.targetPlatform.hasSharedLibraries
+, enableLTO ? stdenv.hostPlatform.hasSharedLibraries
 , texinfo ? null
 , perl ? null # optional, for texi2pod (then pod2man)
 , gmp, mpfr, libmpc, gettext, which, patchelf, binutils
@@ -19,7 +19,7 @@
 , name ? "gcc"
 , libcCross ? null
 , threadsCross ? null # for MinGW
-, crossStageStatic ? false
+, withoutTargetLibc ? false
 , gnused ? null
 , cloog ? null # unused; just for compat with gcc4, as we override the parameter on some places
 , buildPackages
@@ -63,12 +63,12 @@ let majorVersion = "8";
       ++ optional (targetPlatform.libc == "musl") ../libgomp-dont-force-initial-exec.patch
 
       # Obtain latest patch with ../update-mcfgthread-patches.sh
-      ++ optional (!crossStageStatic && targetPlatform.isMinGW && threadsCross.model == "mcf") ./Added-mcf-thread-model-support-from-mcfgthread.patch
+      ++ optional (!withoutTargetLibc && targetPlatform.isMinGW && threadsCross.model == "mcf") ./Added-mcf-thread-model-support-from-mcfgthread.patch
       ++ [ ../libsanitizer-no-cyclades-9.patch ];
 
     /* Cross-gcc settings (build == host != target) */
     crossMingw = targetPlatform != hostPlatform && targetPlatform.libc == "msvcrt";
-    stageNameAddon = if crossStageStatic then "stage-static" else "stage-final";
+    stageNameAddon = if withoutTargetLibc then "stage-static" else "stage-final";
     crossNameAddon = optionalString (targetPlatform != hostPlatform) "${targetPlatform.config}-${stageNameAddon}-";
 
     callFile = lib.callPackageWith {
@@ -89,7 +89,7 @@ let majorVersion = "8";
         binutils
         buildPackages
         cloog
-        crossStageStatic
+        withoutTargetLibc
         enableLTO
         enableMultilib
         enablePlugin
@@ -199,7 +199,10 @@ lib.pipe (stdenv.mkDerivation ({
             )
           '';
 
-  inherit noSysDirs staticCompiler crossStageStatic
+  # kludge to prevent a mass-rebuild; will be removed in a PR sent to staging
+  crossStageStatic = withoutTargetLibc;
+
+  inherit noSysDirs staticCompiler
     libcCross crossMingw;
 
   inherit (callFile ../common/dependencies.nix { })
@@ -277,5 +280,5 @@ lib.pipe (stdenv.mkDerivation ({
 // optionalAttrs (enableMultilib) { dontMoveLib64 = true; }
 ))
 [
-  (callPackage ../common/libgcc.nix   { inherit version langC langCC langJit targetPlatform hostPlatform crossStageStatic; })
+  (callPackage ../common/libgcc.nix   { inherit version langC langCC langJit targetPlatform hostPlatform withoutTargetLibc enableShared; })
 ]

pkgs/development/compilers/gcc/9/default.nix

@@ -9,8 +9,8 @@
 , profiledCompiler ? false
 , langJit ? false
 , staticCompiler ? false
-, enableShared ? !stdenv.targetPlatform.isStatic
-, enableLTO ? !stdenv.hostPlatform.isStatic
+, enableShared ? stdenv.targetPlatform.hasSharedLibraries
+, enableLTO ? stdenv.hostPlatform.hasSharedLibraries
 , texinfo ? null
 , perl ? null # optional, for texi2pod (then pod2man)
 , gmp, mpfr, libmpc, gettext, which, patchelf, binutils
@@ -22,7 +22,7 @@
 , name ? "gcc"
 , libcCross ? null
 , threadsCross ? null # for MinGW
-, crossStageStatic ? false
+, withoutTargetLibc ? false
 , gnused ? null
 , cloog # unused; just for compat with gcc4, as we override the parameter on some places
 , buildPackages
@@ -74,12 +74,12 @@ let majorVersion = "9";
       ++ optional (targetPlatform.libc == "musl" && targetPlatform.isPower) ../ppc-musl.patch
 
       # Obtain latest patch with ../update-mcfgthread-patches.sh
-      ++ optional (!crossStageStatic && targetPlatform.isMinGW && threadsCross.model == "mcf") ./Added-mcf-thread-model-support-from-mcfgthread.patch
+      ++ optional (!withoutTargetLibc && targetPlatform.isMinGW && threadsCross.model == "mcf") ./Added-mcf-thread-model-support-from-mcfgthread.patch
       ;
 
     /* Cross-gcc settings (build == host != target) */
     crossMingw = targetPlatform != hostPlatform && targetPlatform.libc == "msvcrt";
-    stageNameAddon = if crossStageStatic then "stage-static" else "stage-final";
+    stageNameAddon = if withoutTargetLibc then "stage-static" else "stage-final";
     crossNameAddon = optionalString (targetPlatform != hostPlatform) "${targetPlatform.config}-${stageNameAddon}-";
 
     callFile = lib.callPackageWith {
@@ -100,7 +100,7 @@ let majorVersion = "9";
         binutils
         buildPackages
         cloog
-        crossStageStatic
+        withoutTargetLibc
         enableLTO
         enableMultilib
         enablePlugin
@@ -213,7 +213,10 @@ lib.pipe (stdenv.mkDerivation ({
           )
         '';
 
-  inherit noSysDirs staticCompiler crossStageStatic
+  # kludge to prevent a mass-rebuild; will be removed in a PR sent to staging
+  crossStageStatic = withoutTargetLibc;
+
+  inherit noSysDirs staticCompiler
     libcCross crossMingw;
 
   inherit (callFile ../common/dependencies.nix { })
@@ -292,5 +295,5 @@ lib.pipe (stdenv.mkDerivation ({
 // optionalAttrs (enableMultilib) { dontMoveLib64 = true; }
 )
 ) [
-  (callPackage ../common/libgcc.nix   { inherit version langC langCC langJit targetPlatform hostPlatform crossStageStatic; })
+  (callPackage ../common/libgcc.nix   { inherit version langC langCC langJit targetPlatform hostPlatform withoutTargetLibc enableShared; })
 ]

pkgs/development/compilers/gcc/common/configure-flags.nix

@@ -1,7 +1,7 @@
 { lib, stdenv
 , targetPackages
 
-, crossStageStatic, libcCross
+, withoutTargetLibc, libcCross
 , threadsCross
 , version
 
@@ -59,14 +59,14 @@ let
       "--with-as=${if targetPackages.stdenv.cc.bintools.isLLVM then binutils else targetPackages.stdenv.cc.bintools}/bin/${targetPlatform.config}-as"
       "--with-ld=${targetPackages.stdenv.cc.bintools}/bin/${targetPlatform.config}-ld"
     ]
-    ++ (if crossStageStatic then [
+    ++ (if withoutTargetLibc then [
       "--disable-libssp"
       "--disable-nls"
       "--without-headers"
       "--disable-threads"
       "--disable-libgomp"
       "--disable-libquadmath"
-      "--disable-shared"
+      (lib.enableFeature enableShared "shared")
       "--disable-libatomic" # requires libc
       "--disable-decimal-float" # requires libc
       "--disable-libmpx" # requires libc
@@ -112,7 +112,7 @@ let
       "--with-mpfr-lib=${mpfr.out}/lib"
       "--with-mpc=${libmpc}"
     ]
-    ++ lib.optionals (!crossStageStatic) [
+    ++ lib.optionals (!withoutTargetLibc) [
       (if libcCross == null
        then "--with-native-system-header-dir=${lib.getDev stdenv.cc.libc}/include"
        else "--with-native-system-header-dir=${lib.getDev libcCross}${libcCross.incdir or "/include"}")

pkgs/development/compilers/gcc/common/dependencies.nix

@@ -30,7 +30,7 @@
 , javaAwtGtk ? false
 , langAda ? false
 , langGo ? false
-, crossStageStatic ? null
+, withoutTargetLibc ? null
 , threadsCross ? null
 }:
 
@@ -88,5 +88,5 @@ in
   ;
 
   # threadsCross.package after gcc6 so i assume its okay for 4.8 and 4.9 too
-  depsTargetTarget = optionals (!crossStageStatic && threadsCross != { } && threadsCross.package != null) [ threadsCross.package ];
+  depsTargetTarget = optionals (!withoutTargetLibc && threadsCross != { } && threadsCross.package != null) [ threadsCross.package ];
 }

pkgs/development/compilers/gcc/common/extra-target-flags.nix

@@ -1,4 +1,4 @@
-{ lib, stdenv, crossStageStatic, langD ? false, libcCross, threadsCross }:
+{ lib, stdenv, withoutTargetLibc, langD ? false, libcCross, threadsCross }:
 
 let
   inherit (stdenv) hostPlatform targetPlatform;
@@ -11,23 +11,23 @@ in
   EXTRA_FLAGS_FOR_TARGET = let
       mkFlags = dep: langD: lib.optionals (targetPlatform != hostPlatform && dep != null && !langD) ([
         "-O2 -idirafter ${lib.getDev dep}${dep.incdir or "/include"}"
-      ] ++ lib.optionals (! crossStageStatic) [
+      ] ++ lib.optionals (! withoutTargetLibc) [
         "-B${lib.getLib dep}${dep.libdir or "/lib"}"
       ]);
     in mkFlags libcCross langD
-       ++ lib.optionals (!crossStageStatic) (mkFlags (threadsCross.package or null) langD)
+       ++ lib.optionals (!withoutTargetLibc) (mkFlags (threadsCross.package or null) langD)
     ;
 
   EXTRA_LDFLAGS_FOR_TARGET = let
       mkFlags = dep: lib.optionals (targetPlatform != hostPlatform && dep != null) ([
         "-Wl,-L${lib.getLib dep}${dep.libdir or "/lib"}"
-      ] ++ (if crossStageStatic then [
+      ] ++ (if withoutTargetLibc then [
           "-B${lib.getLib dep}${dep.libdir or "/lib"}"
         ] else [
           "-Wl,-rpath,${lib.getLib dep}${dep.libdir or "/lib"}"
           "-Wl,-rpath-link,${lib.getLib dep}${dep.libdir or "/lib"}"
       ]));
     in mkFlags libcCross
-       ++ lib.optionals (!crossStageStatic) (mkFlags (threadsCross.package or null))
+       ++ lib.optionals (!withoutTargetLibc) (mkFlags (threadsCross.package or null))
     ;
 }

pkgs/development/compilers/gcc/common/libgcc.nix

@@ -4,11 +4,14 @@
 , langC
 , langCC
 , langJit
+, enableShared
 , targetPlatform
 , hostPlatform
-, crossStageStatic
+, withoutTargetLibc
 }:
 
+assert !stdenv.targetPlatform.hasSharedLibraries -> !enableShared;
+
 drv: lib.pipe drv
 
 ([
@@ -16,8 +19,8 @@ drv: lib.pipe drv
   (pkg: pkg.overrideAttrs (previousAttrs:
     lib.optionalAttrs (
       targetPlatform != hostPlatform &&
-      targetPlatform.libc == "msvcrt" &&
-      crossStageStatic
+      enableShared &&
+      withoutTargetLibc
     ) {
       makeFlags = [ "all-gcc" "all-target-libgcc" ];
       installTargets = "install-gcc install-target-libgcc";
@@ -31,11 +34,15 @@ drv: lib.pipe drv
 lib.optional (lib.versionAtLeast version "11.0")
 
 (let
+  targetPlatformSlash =
+    if hostPlatform.config == targetPlatform.config
+    then ""
+    else "${targetPlatform.config}/";
+
   enableLibGccOutput =
-    (with stdenv; targetPlatform == hostPlatform) &&
     !langJit &&
     !stdenv.hostPlatform.isDarwin &&
-    !stdenv.hostPlatform.isStatic
+    enableShared
     ;
 
 in
@@ -50,6 +57,10 @@ in
     lib.optionalString (!langC) ''
       rm -f $out/lib/libgcc_s.so*
     ''
+    + lib.optionalString (hostPlatform.config != targetPlatform.config) ''
+      mkdir -p $lib/lib/
+      ln -s ${targetPlatformSlash}lib $lib/lib
+    ''
 
     # TODO(amjoseph): remove the `libgcc_s.so` symlinks below and replace them
     # with a `-L${gccForLibs.libgcc}/lib` in cc-wrapper's
@@ -62,10 +73,10 @@ in
     + lib.optionalString enableLibGccOutput (''
       # move libgcc from lib to its own output (libgcc)
       mkdir -p $libgcc/lib
-      mv    $lib/lib/libgcc_s.so      $libgcc/lib/
-      mv    $lib/lib/libgcc_s.so.1    $libgcc/lib/
-      ln -s $libgcc/lib/libgcc_s.so   $lib/lib/
-      ln -s $libgcc/lib/libgcc_s.so.1 $lib/lib/
+      mv    $lib/${targetPlatformSlash}lib/libgcc_s.so      $libgcc/lib/
+      mv    $lib/${targetPlatformSlash}lib/libgcc_s.so.1    $libgcc/lib/
+      ln -s $libgcc/lib/libgcc_s.so   $lib/${targetPlatformSlash}lib/
+      ln -s $libgcc/lib/libgcc_s.so.1 $lib/${targetPlatformSlash}lib/
     ''
     #
     # Nixpkgs ordinarily turns dynamic linking into pseudo-static linking:

pkgs/development/compilers/gcc/common/pre-configure.nix

@@ -1,10 +1,13 @@
-{ lib, version, buildPlatform, hostPlatform, targetPlatform
+{ lib
+, stdenv
+, version, buildPlatform, hostPlatform, targetPlatform
 , gnat-bootstrap ? null
 , langAda ? false
 , langJava ? false
 , langJit ? false
 , langGo
-, crossStageStatic
+, withoutTargetLibc
+, enableShared
 , enableMultilib
 }:
 
@@ -105,10 +108,21 @@ in lib.optionalString (hostPlatform.isSunOS && hostPlatform.is64bit) ''
 # gcc->clang "cross"-compilation manages to evade it: there
 # hostPlatform != targetPlatform, hostPlatform.config == targetPlatform.config.
 # We explicitly inhibit libc headers use in this case as well.
-+ lib.optionalString (targetPlatform != hostPlatform && crossStageStatic) ''
++ lib.optionalString (targetPlatform != hostPlatform && withoutTargetLibc) ''
   export inhibit_libc=true
 ''
 
+# Trick to build a gcc that is capable of emitting shared libraries *without* having the
+# targetPlatform libc available beforehand.  Taken from:
+#   https://web.archive.org/web/20170222224855/http://frank.harvard.edu/~coldwell/toolchain/
+#   https://web.archive.org/web/20170224235700/http://frank.harvard.edu/~coldwell/toolchain/t-linux.diff
++ lib.optionalString (targetPlatform != hostPlatform && withoutTargetLibc && enableShared)
+  (lib.optionalString (!stdenv.targetPlatform.isPower) ''
+    echo 'libgcc.a: crti.o crtn.o' >> libgcc/Makefile.in
+  '' + ''
+    echo 'SHLIB_LC=' >> libgcc/Makefile.in
+  '')
+
 + lib.optionalString (!enableMultilib && hostPlatform.is64bit && !hostPlatform.isMips64n32) ''
   export linkLib64toLib=1
 ''

pkgs/os-specific/windows/default.nix

@@ -20,7 +20,7 @@ lib.makeScope newScope (self: with self; {
   crossThreadsStdenv = overrideCC crossLibcStdenv
     (if stdenv.hostPlatform.useLLVM or false
      then buildPackages.llvmPackages_8.clangNoLibcxx
-     else buildPackages.gccCrossStageStatic.override (old: {
+     else buildPackages.gccWithoutTargetLibc.override (old: {
        bintools = old.bintools.override {
          libc = libcCross;
        };

pkgs/top-level/all-packages.nix

@@ -14417,7 +14417,7 @@ with pkgs;
   xbursttools = callPackage ../tools/misc/xburst-tools {
     # It needs a cross compiler for mipsel to build the firmware it will
     # load into the Ben Nanonote
-    gccCross = pkgsCross.ben-nanonote.buildPackages.gccCrossStageStatic;
+    gccCross = pkgsCross.ben-nanonote.buildPackages.gccWithoutTargetLibc;
     autoconf = buildPackages.autoconf269;
   };
 
@@ -15339,7 +15339,7 @@ with pkgs;
     dontStrip = true;
   }));
 
-  gccCrossLibcStdenv = overrideCC stdenv buildPackages.gccCrossStageStatic;
+  gccCrossLibcStdenv = overrideCC stdenv buildPackages.gccWithoutTargetLibc;
 
   crossLibcStdenv =
     if stdenv.hostPlatform.useLLVM or false || stdenv.hostPlatform.isDarwin
@@ -15348,7 +15348,7 @@ with pkgs;
 
   # The GCC used to build libc for the target platform. Normal gccs will be
   # built with, and use, that cross-compiled libc.
-  gccCrossStageStatic = assert stdenv.targetPlatform != stdenv.hostPlatform; let
+  gccWithoutTargetLibc = assert stdenv.targetPlatform != stdenv.hostPlatform; let
     libcCross1 = binutilsNoLibc.libc;
     in wrapCCWith {
       cc = gccFun {
@@ -15360,12 +15360,10 @@ with pkgs;
 
         isl = if !stdenv.isDarwin then isl_0_20 else null;
 
-        # just for stage static
-        crossStageStatic = true;
+        withoutTargetLibc = true;
         langCC = false;
         libcCross = libcCross1;
         targetPackages.stdenv.cc.bintools = binutilsNoLibc;
-        enableShared = false;
       };
       bintools = binutilsNoLibc;
       libc = libcCross1;