pluggable_runcore branch merge broke build on darwin

[dukeleto]

config/gen/platform/generic/hires_timer.c: In function ‘Parrot_hires_get_time’:
config/gen/platform/generic/hires_timer.c:41: warning: implicit declaration of function ‘clock_gettime’
config/gen/platform/generic/hires_timer.c:41: warning: nested extern declaration of ‘clock_gettime’
config/gen/platform/generic/hires_timer.c:41: error: ‘CLOCK_PROF’ undeclared (first use in this function)
config/gen/platform/generic/hires_timer.c:41: error: (Each undeclared identifier is reported only once
config/gen/platform/generic/hires_timer.c:41: error: for each function it appears in.)
make: *** [src/platform.o] Error 1

[dukeleto]

darbelo++ gave me a patch with turned into r41087, which seems to fix the build.