Moved $FreeBSD$ to the beginning of the file.

Don't put the name of the file in a comment. $FreeBSD$ gives more than
enough about the file's pathname.

Fixed misdescription of the file. It isn't the whole unified Makefile...

Moved the settings of WERROR and of the standard extra CFLAGS
-finline-limit and -fno-strict-aliasing to a less wrong place. They
were in the section for profiling.