sourcebuild.texi (Front End Directory): Don't make references to libsubdir, it's not part of the interface to frontends.

	* doc/sourcebuild.texi (Front End Directory): Don't make references
	to libsubdir, it's not part of the interface to frontends.
	* doc/install.texi (Configuration): Help users read faster by saying
	that GCC's configure options are the standard autoconf ones.
	Mention --libdir.  Update the default rules for finding the
	assembler.  Don't use libsubdir since we haven't said what it means.
	(Specific): In the Solaris 7 notes, update the place to put the
	assembler.
	* doc/invoke.texi: Update lib/gcc-lib to lib/gcc.
	* doc/cpp.texi (Search Path): Actually, the search path
	depends on libdir, which can relocate with cpp.
	* doc/tm.texi (Driver): Don't document STANDARD_EXEC_PREFIX, it's
	now a private interface between the Makefile and the driver.

From-SVN: r70073