man: Add a timespec(3bsd) alias to timeval(3bsd)

Even though man-pages project now includes man pages for system data
types, we still include these for any other system that does not have
them, to provide a self-contained project with code and documentation.

man/Makefile.am

@@ -223,6 +223,7 @@ dist_man_MANS = \
 	timercmp.3bsd \
 	timerisset.3bsd \
 	timersub.3bsd \
+	timespec.3bsd \
 	timespecadd.3bsd \
 	timespecclear.3bsd \
 	timespeccmp.3bsd \

man/timespec.3bsd

+.so man3/timeval.3bsd