Merge pull request #251942 from risicle/ris-fortify-headers-disable-non-gcc

cc-wrapper: don't use `fortify-headers` for non-gcc compilers

pkgs/build-support/cc-wrapper/default.nix

···
 
   includeFortifyHeaders' = if includeFortifyHeaders != null
     then includeFortifyHeaders
-    else targetPlatform.libc == "musl";
+    else (targetPlatform.libc == "musl" && isGNU);
 
   # Prefix for binaries. Customarily ends with a dash separator.
   #