Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

MFC r259473:

Enable llvm's integrated assembler for PowerPC, since it should now be
good enough for typical usage.

Requested by: rdivacky

Enable llvm's integrated assembler for PowerPC, since it should now be
good enough for typical usage.

Requested by: rdivacky
MFC after: 1 week