Add support for PowerPC to devel/nspr.
There were two things missing in the nspr port that prevented it from
being properly compiled on PowerPC:
- A string definition of the processor platform ("powerpc").
- Definitions of byte ordering and sizes of standard C types.
I copied the second list of definitions from _linux.cfg. The values used
by _openbsd.cfg and _netbsd.cfg are not accurate (size and alignment of
int64 is incorrect).
Approved by: marcus