This separates the 32-bit sysv/linux/bsd code from the 64-bit linux

code, and makes it possible to link code compiled with different
options to those used to compile libffi.  For example, a
-mlong-double-128 libffi can be used with -mlong-double-64 code.

Using the return value area as a place to pass parameters wasn't such
a good idea, causing a failure of cls_ulonglong.c.  I didn't see this
when running the mainline gcc libffi testsuite because that version of
the test is inferior to the upstreamm libffi test.

Using NUM_FPR_ARG_REGISTERS rather than NUM_FPR_ARG_REGISTERS64 meant
that a parameter save area could be allocated before it was strictly
necessary.  Wrong but harmless.  Found when splitting apart ffi.c
into 32-bit and 64-bit support.

src/powerpc/sysv.S

@@ -30,7 +30,7 @@
 #include <ffi.h>
 #include <powerpc/asm.h>
 
-#ifndef __powerpc64__
+#ifndef POWERPC64
 	.globl ffi_prep_args_SYSV
 ENTRY(ffi_call_SYSV)
 .LFB1:
@@ -213,8 +213,8 @@ END(ffi_call_SYSV)
       .uleb128  0x1c
       .align 2
 .LEFDE1:
-#endif
 
 #if defined __ELF__ && defined __linux__
 	.section	.note.GNU-stack,"",@progbits
 #endif
+#endif