Patch/RFC: -mlongcall and #pragma longcall for PowerPC

[David Edelsohn]

>>>>> Zack Weinberg writes:

Zack> Only that I hadn't noticed all the others were the other way around.
Zack> I've swapped them in my tree along with some other fixes.

	Thanks.

>> Also, when you document the longcall pragma, would you please make
>> it clear to which GCC configurations it applies.  SVR4?  eABI?  It
>> definitely does not apply to AIX and Darwin.

Zack> Huh? As far as I can tell this is a universal issue.  In fact, I
Zack> modeled the SVR4 indirect call patterns after the AIX ones.  It's
Zack> about getting around the 64-megabyte limit on 'b <symbol>', not any
Zack> ABI specific issue.

	The AIX patterns don't look at the cookie and the "call" expander
does not create RTL with the cookie.  The remainder of the sysv patterns
would match the AIX patterns.

David