Replace macOS CC path with relative path

After this change #8495 the path
to CC embedded in this file was absolute, which caused cache misses for
all compile actions. This change depends on this file relative to the
cc_wrapper itself instead.

Fixes #10184

Closes #10185.

PiperOrigin-RevId: 279960066

tools/cpp/osx_cc_configure.bzl

@@ -83,11 +83,12 @@ def configure_osx_toolchain(repository_ctx, overriden_tools):
         # the C++ actions behave consistently.
         cc = repository_ctx.path("wrapped_clang")
 
+        cc_path = '"$(dirname "$0")"/wrapped_clang'
         repository_ctx.template(
             "cc_wrapper.sh",
             paths["@bazel_tools//tools/cpp:osx_cc_wrapper.sh.tpl"],
             {
-                "%{cc}": escape_string(str(cc)),
+                "%{cc}": escape_string(cc_path),
                 "%{env}": escape_string(get_env(repository_ctx)),
             },
         )