libbfd.texi zero size

Pattern rules in doc/local.mk exist that specify how to make
libbfd.texi from libfd.h or libbfd.c.  Since both files exist and the
libbfd.h rule is first, libbfd.h is used.  libbfd.h doesn't contain
the documentation..

	* doc/local.mk (doc/%stamp): Put rule making this from %.c
	before %.h rule.
	* Makefile.in: Regenerate.
	* libbfd.c (Byte swapping routines): Don't omit description.