bazel_5: get libtool from path

We're resolving most cc toolchain tools from the path and environment variables, but we hardcode libtool. This makes it hard to point libtool to the specific one you need, for example to work around issues like
https://github.com/NixOS/nixpkgs/pull/180251#issuecomment-1200096413. Make it consistent by getting libtool from path too, like other cc toolchain tools.

pkgs/development/tools/build-managers/bazel/bazel_5/default.nix

@@ -377,9 +377,10 @@ stdenv.mkDerivation rec {
       # invocations of gcc to clang, but vanilla clang doesn't
       sed -i -e 's;_find_generic(repository_ctx, "gcc", "CC", overriden_tools);_find_generic(repository_ctx, "clang", "CC", overriden_tools);g' tools/cpp/unix_cc_configure.bzl
 
-      sed -i -e 's;/usr/bin/libtool;${cctools}/bin/libtool;g' tools/cpp/unix_cc_configure.bzl
+      sed -i -e 's;"/usr/bin/libtool";_find_generic(repository_ctx, "libtool", "LIBTOOL", overriden_tools);g' tools/cpp/unix_cc_configure.bzl
       wrappers=( tools/cpp/osx_cc_wrapper.sh tools/cpp/osx_cc_wrapper.sh.tpl )
       for wrapper in "''${wrappers[@]}"; do
+        sed -i -e "s,/usr/bin/gcc,${stdenv.cc}/bin/clang,g" $wrapper
         sed -i -e "s,/usr/bin/install_name_tool,${cctools}/bin/install_name_tool,g" $wrapper
       done
     '';