feat: trim the build to the minimum

on a slow finicky target machine, no time to pull gcc

Makefile

@@ -1,15 +0,0 @@
-PREFIX ?= /usr/local
-SHARE ?= $(PREFIX)/share/disko
-
-all:
-
-SOURCES = disko cli.nix default.nix types.nix
-
-install:
-	mkdir -p $(PREFIX)/bin $(SHARE)
-	sed \
-		-e "s|libexec_dir=\".*\"|libexec_dir=\"$(SHARE)\"|" \
-		-e "s|#!/usr/bin/env.*|#!/usr/bin/env bash|" \
-		disko > $(PREFIX)/bin/disko
-	chmod 755 $(PREFIX)/bin/disko
-	cp -r $(SOURCES) $(SHARE)

flake.nix

@@ -9,12 +9,38 @@
       inherit (nixpkgs) lib;
     };
     packages.x86_64-linux.disko = let
+      inherit (nixpkgs) lib;
       pkgs = nixpkgs.legacyPackages.x86_64-linux;
-    in pkgs.stdenv.mkDerivation {
+      inclFiles = {src, name}: files: lib.cleanSourceWith {
+        inherit src name;
+        filter = _path: _type: _type == "regular"
+          && lib.any (file: builtins.baseNameOf _path == file) files;
+      };
+    in derivation rec{
+      system = "x86_64-linux";
       name = "disko";
-      src = ./.;
+      builder = "/bin/sh";
+      PATH    = "${pkgs.coreutils}/bin:${pkgs.gnused}/bin";
+      passAsFile = ["buildPhase"];
+      buildPhase = ''
+        mkdir -p $out/bin $out/share/disko
+	cp -r $src/* $out/share/disko
+	sed \
+	  -e "s|libexec_dir=\".*\"|libexec_dir=\"$out/share/disko\"|" \
+	  -e "s|#!/usr/bin/env.*|#!/usr/bin/env bash|" \
+	  $src/disko > $out/bin/disko
+	chmod 755 $out/bin/disko
+      '';
+      args = ["-c" ". $buildPhasePath"];
+      src = inclFiles { inherit name; src = ./.; } [
+        "disko"
+        "cli.nix"
+        "default.nix"
+        "types.nix"
+        "options.nix"
+      ];
+    } // {
       meta.description = "Format disks with nix-config";
-      installFlags = [ "PREFIX=$(out)" ];
     };
     packages.x86_64-linux.default = self.packages.x86_64-linux.disko;
     checks.x86_64-linux = let