* libc/machine/powerpc/vfprintf.c(__VFPRINTF_R)[__ALTIVEC__]: Restore
the original format specifier when looping for vectors to compensate
for any changes made in vector %g format processing.
Also add syntax checking for various invalid scenarios
involving vector format extensions.
* libc/machine/powerpc/vfscanf.c(__VFSCANF_R)[__ALTIVEC__]: Fix
return code setting for vector formats. Also treat vector
separator mismatch as a match error instead of an input error.
Perform some syntax checking for vector formats.