The apple assembler for arm64 can handle the gnu binutils style
macros just fine, so there is no need to duplicate all of these
macros in two syntaxes, when the new one works fine in all cases.
We already require a new enough assembler to support the gnu binutils
style features since we use the .rept directive in a few places.
The .align directive takes an argument in number of bits, i.e. the
actual alignment is 2^n. Previously building with binutils failed,
since 16 isn't a valid parameter to .align, the maximum is 15.
Thus, this makes the code try to align to 16 bytes, instead of aligning
to 65536 bytes.
This fixes building for android.
This also clears up the same mistake in the aarch64 code, even though
that one built just fine.
