#277 Missing <time.h> include

[Thomas Petazzoni]

The nanosleep() function prototype is in <time.h>, so this header file
should be included whenever nanosleep() is used. Not including it
causes some issues when building OProfile against a non-thread capable
version of the uClibc C library, probably because in such situation,
<time.h> does not get included by another header.

See http://autobuild.buildroot.org/results/d28/d28447c1241ce3dd237710e388d799139d7d613d/build-end.log.

The attached patch fixes those issues.

[William Cohen]

This patch looks good and has been added to the git repository.