[build] Don't try to find out the exact prototype of gettimeofday().

[build] Don't try to find out the exact prototype of gettimeofday().

First of all, according to POSIX gettimeofday() has the following protype:

int gettimeofday(struct timeval *restrict tp, void restrict* tzp);

so GETTIMEOFDAY_DOTS is not really necessary.

Secondly, we always pass NULL as the second argument, so its type does not
really matter.