Fix handling of function values for -fgo-c-header to generate FuncVal*,
not simply FuncVal.
While we're here change runtime.nanotime to use clock_gettime with
CLOCK_MONOTONIC, rather than gettimeofday. This is what the gc library
does. It provides nanosecond precision and a monotonic clock.
Reviewed-on: https://go-review.googlesource.com/31232
From-SVN: r241197