xcompile: Separate flags from clang executable

We already have a CFLAGS variable - Use it for all of the flags.

Change-Id: I22b4c5cf24b8743e85ffab29ddcccdc6c732ea3b
Signed-off-by: Martin Roth <martinroth@google.com>
Reviewed-on: https://review.coreboot.org/12840
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
1 file changed