gcc: allow stripping gcc libraries

When cross compiling to the same kernel / arch combination, it is safe
to use strip of libraries. This happens when cross-compiling musl
programs. dontStrip is now set in each gcc compiler instead of in
gcc/builder.sh.

Fixes NixOS#75476

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

@@ -23,8 +23,8 @@
 , threadsCross ? null # for MinGW
 , crossStageStatic ? false
 , # Strip kills static libs of other archs (hence no cross)
-  stripped ? stdenv.hostPlatform == stdenv.buildPlatform
-          && stdenv.targetPlatform == stdenv.hostPlatform
+  stripped ? stdenv.hostPlatform.system == stdenv.buildPlatform.system
+          && stdenv.targetPlatform.system == stdenv.hostPlatform.system
 , gnused ? null
 , cloog # unused; just for compat with gcc4, as we override the parameter on some places
 , buildPackages

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

@@ -31,8 +31,8 @@
 , threadsCross ? null # for MinGW
 , crossStageStatic ? false
 , # Strip kills static libs of other archs (hence no cross)
-  stripped ? stdenv.hostPlatform == stdenv.buildPlatform
-          && stdenv.targetPlatform == stdenv.hostPlatform
+  stripped ? stdenv.hostPlatform.system == stdenv.buildPlatform.system
+          && stdenv.targetPlatform.system == stdenv.hostPlatform.system
 , gnused ? null
 , cloog # unused; just for compat with gcc4, as we override the parameter on some places
 , buildPackages

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

@@ -21,8 +21,8 @@
 , threadsCross ? null # for MinGW
 , crossStageStatic ? false
 , # Strip kills static libs of other archs (hence no cross)
-  stripped ? stdenv.hostPlatform == stdenv.buildPlatform
-          && stdenv.targetPlatform == stdenv.hostPlatform
+  stripped ? stdenv.hostPlatform.system == stdenv.buildPlatform.system
+          && stdenv.targetPlatform.system == stdenv.hostPlatform.system
 , gnused ? null
 , cloog # unused; just for compat with gcc4, as we override the parameter on some places
 , buildPackages

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

@@ -21,8 +21,8 @@
 , threadsCross ? null # for MinGW
 , crossStageStatic ? false
 , # Strip kills static libs of other archs (hence no cross)
-  stripped ? stdenv.hostPlatform == stdenv.buildPlatform
-          && stdenv.targetPlatform == stdenv.hostPlatform
+  stripped ? stdenv.hostPlatform.system == stdenv.buildPlatform.system
+          && stdenv.targetPlatform.system == stdenv.hostPlatform.system
 , gnused ? null
 , cloog # unused; just for compat with gcc4, as we override the parameter on some places
 , buildPackages

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

@@ -24,8 +24,8 @@
 , threadsCross ? null # for MinGW
 , crossStageStatic ? false
 , # Strip kills static libs of other archs (hence no cross)
-  stripped ? stdenv.hostPlatform == stdenv.buildPlatform
-          && stdenv.targetPlatform == stdenv.hostPlatform
+  stripped ? stdenv.hostPlatform.system == stdenv.buildPlatform.system
+          && stdenv.targetPlatform.system == stdenv.hostPlatform.system
 , gnused ? null
 , cloog # unused; just for compat with gcc4, as we override the parameter on some places
 , buildPackages

pkgs/development/compilers/gcc/builder.sh

@@ -144,9 +144,9 @@ if test "$noSysDirs" = "1"; then
     fi
 fi
 
-if test -n "${targetConfig-}"; then
-    # The host strip will destroy some important details of the objects
-    dontStrip=1
+if [ -n "${targetConfig-}" ] && [ -z "${stripDebugList-}" ]; then
+    # if stripping gcc, include target directory too
+    stripDebugList="lib lib32 lib64 libexec bin sbin $targetConfig"
 fi
 
 eval "$oldOpts"