Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

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