[gmp] [powerpc] GMP build is broken because asm {...} syntax has been removed from latest toolchains

[Douglas Mencken]

> I have read and reread your reply, but I cannot make sense of it.

cntlz and cntlzw are the same. Same machine code.
ai and addic are the same. Same machine code.

{ai|addic} 3,4 is the same as both ai 3,4 and addic 3,4. There're no
difference at all between all three of them. Absolutely. But the
latter (addic) is better and much more readable (add immediate,
affecting carrying bit).
It's a some convention how to turn letters into machine-readable
bytes. And this is controlled by assemblers.