Update "configure.in" in comments and doco

bfd/
	* Makefile.am: Update "configure.in" comments.
	* PORTING: Likewise.
	* aoutx.h: Likewise.
	* configure.host: Likewise.
	* doc/bfdint.texi: Likewise.
	* targets.c: Likewise.
	* warning.m4: Likewise.
	* Makefile.in: Regenerate.
gas/
	* doc/internals.texi: Update "configure.in" comments.
	* acinclude.m4: Likewise.
	* config/tc-sparc.c: Likewise.
ld/
	* configure.ac: Update "configure.in" comments.
	* configure: Regenerate.
daily update
Rid libdummy.a from lto.exp

libdummy.a is used to make run_cc_link_tests compile objects and
archive them.  libdummy.a isn't used.  What we're really doing is
preventing a final link.  So do that directly.

	* lib/ld-lib.exp (run_ld_link_tests): Stop after assembling objects
	if binfile is empty.
	(run_ld_link_exec_tests, run_cc_link_tests): Likewise.  Tidy
	status checks.
	* ld-plugin/lto.exp: Don't use libdummy.a trick to compile objects.
	Instead use an empty output file.