diff --git a/pkgs/build-support/cc-wrapper/cc-wrapper.sh b/pkgs/build-support/cc-wrapper/cc-wrapper.sh
index 3ccdc34db5b2..99eb63f40edf 100644
--- a/pkgs/build-support/cc-wrapper/cc-wrapper.sh
+++ b/pkgs/build-support/cc-wrapper/cc-wrapper.sh
@@ -55,7 +55,7 @@ while [ $n -lt ${#params[*]} ]; do
         nonFlagArgs=1
     elif [ "$p" = -m32 ]; then
         if [ -e @out@/nix-support/dynamic-linker-m32 ]; then
-            NIX_LDFLAGS="$NIX_LDFLAGS -dynamic-linker $(cat @out@/nix-support/dynamic-linker-m32)"
+            NIX_LDFLAGS+=" -dynamic-linker $(cat @out@/nix-support/dynamic-linker-m32)"
         fi
     fi
     n=$((n + 1))
@@ -111,9 +111,9 @@ fi
 
 if [[ "$isCpp" = 1 ]]; then
     if [[ "$cppInclude" = 1 ]]; then
-        NIX_CFLAGS_COMPILE="$NIX_CFLAGS_COMPILE ${NIX_CXXSTDLIB_COMPILE-@default_cxx_stdlib_compile@}"
+        NIX_CFLAGS_COMPILE+=" ${NIX_CXXSTDLIB_COMPILE-@default_cxx_stdlib_compile@}"
     fi
-    NIX_CFLAGS_LINK="$NIX_CFLAGS_LINK $NIX_CXXSTDLIB_LINK"
+    NIX_CFLAGS_LINK+=" $NIX_CXXSTDLIB_LINK"
 fi
 
 LD=@ldPath@/ld
diff --git a/pkgs/build-support/cc-wrapper/ld-wrapper.sh b/pkgs/build-support/cc-wrapper/ld-wrapper.sh
index 056cfa920535..4b3906a2e10f 100644
--- a/pkgs/build-support/cc-wrapper/ld-wrapper.sh
+++ b/pkgs/build-support/cc-wrapper/ld-wrapper.sh
@@ -79,7 +79,7 @@ if [ "$NIX_DONT_SET_RPATH" != 1 ]; then
         case $libPath in
             *\ $path\ *) return 0 ;;
         esac
-        libPath="$libPath $path "
+        libPath+=" $path "
     }
 
     addToRPath() {
@@ -90,12 +90,12 @@ if [ "$NIX_DONT_SET_RPATH" != 1 ]; then
         case $rpath in
             *\ $1\ *) return 0 ;;
         esac
-        rpath="$rpath $1 "
+        rpath+=" $1 "
     }
 
     libs=""
     addToLibs() {
-        libs="$libs $1"
+        libs+=" $1"
     }
 
     rpath=""