Link RS compatibility files with libc and make bcc_compat a regular dep.

If we don't do "-lc", we end up missing symbols like "memset" on our non-NEON
builds. It also makes more sense to have bcc_compat as a standard dependency
for now, since it occasionally changes the way we compile/link our source
files.

Change-Id: I4b0ead66caa7c72fb7733db8804a33faa5350930