Fix up a few minor issues with bcc standalone executable.

1) Default to -O3. This is to match the behavior of the integrated compiler
   in libbcc today.
2) Actually run the config() step on the RSCompilerDriver. I previously
   removed the invocation here, since it wasn't doing what we actually wanted
   by default. This change restores the use of config().
3) In running the config() step mentioned in 2), we actually now respect
   the -mtriple compiler flag when run on the host. Device-side compiles
   will always use the target architecture. This makes it easier to generate
   multiple resulting object files for different architectures.

Change-Id: I623ee8eec3d6c42375973e7b7e27f0800ea8ca48
1 file changed