Backport of "gs: look for google_cloud_cpp_storage.pc" into 1.20
Backport of !1815 (merged) "gs: look for google_cloud_cpp_storage.pc".
Commits:
- 1f02f248 gs: look for google_cloud_cpp_storage.pc
Backport of !1815 (merged) "gs: look for google_cloud_cpp_storage.pc".
Commits: