WIP Pass cc_wrapper its path via env var

The inherited RUNFILES_* environment variables aren't correct. Pass in a
path to try and find the correct directory/manifest. Only prints
currently.

Author: iteratee

haskell/cc.bzl

@@ -147,6 +147,7 @@ def cc_interop_info(ctx, override_cc_toolchain = None):
         env["CC_WRAPPER_PLATFORM"] = "linux"
 
     env["CC_WRAPPER_CC_PATH"] = real_cc_path
+    env["CC_WRAPPER_PATH"] = cc_wrapper.executable.path
     env["CC_WRAPPER_CPU"] = cc_toolchain.cpu
 
     cc_libraries_info = deps_HaskellCcLibrariesInfo(

haskell/private/cc_wrapper.py.tpl

@@ -1026,6 +1026,10 @@ def find_cc():
         # being called from a GHCi REPL then we need to find this wrapper
         # script using Bazel runfiles.
         r = bazel_runfiles.Create()
+        if r is None:
+            exe_path = os.environ.get("CC_WRAPPER_PATH", None)
+            if exe_path is not None:
+                r = bazel_runfiles.CreateDirectoryBased(exe_path + ".runfiles")
         cc = r.Rlocation("/".join([WORKSPACE, CC]))
         if cc is None and is_windows():
             # We must use "/" instead of os.path.join on Windows, because the