us when <sys/pmc.h> is included.
o Replace "#if __i386__" and "#if __amd64__" with the equivalent of
"#ifdef __i386__" and "#ifdef __amd64__" (resp.) These tokens are
not defined on all platforms.
o Conditionally compile pmc_parse_mask() on i386 and amd64 only. It's
only referenced there. This will change when support for other
platforms is added, of course.
Ok'd by: jkoshy@
