bazelisk-env: fix gcc linking against nixos libc

pkgs/bazelisk-env/default.nix

@@ -27,7 +27,7 @@ buildFHSUserEnv {
   targetPkgs = pkgs: with pkgs; [
     # include no more than this
     # crt1.o is already taken care of by buildFHSEnv.nix
-    gcc_multi.out
+    (pkgs.callPackage ./gcc_multi_patched.nix {})
 
     binutils
     pkg-config
@@ -38,6 +38,7 @@ buildFHSUserEnv {
     which
     python3
     patch
+    curl
 
     # debugging
     iputils

pkgs/bazelisk-env/gcc_multi_patched.nix

@@ -0,0 +1,23 @@
+{
+  gcc_multi,
+  stdenv,
+}:
+
+stdenv.mkDerivation {
+  name = gcc_multi.name + "-fhs";
+
+  src = gcc_multi;
+
+  buildPhase = ''
+    find . -type f -exec sed -i \
+      -e s,${gcc_multi.out},$out,g \
+      -e s,${gcc_multi.cc.lib},,g \
+      -e s,${gcc_multi.libc},,g \
+      -e s,${gcc_multi.libc.dev},/usr,g \
+      {} +
+  '';
+
+  installPhase = ''
+    cp -rp . $out
+  '';
+}