Makefile.in: Set gcc_version directly, not via substitution.

	* Makefile.in: Set gcc_version directly, not via substitution.
	(libsubdir): Use $(gcc_version), not $(version).
	(mkheaders.almost): New rule.
	(mkheaders): Generate from mkheaders.almost.
	(clean): Also delete mkheaders.almost.
	* aclocal.m4: Do not include ../config/gcc-version.m4.
	* configure.ac: Do not invoke TL_AC_GCC_VERSION.  Generate
	mkheaders.almost from mkheaders.in.
	* configure: Regenerate.

From-SVN: r96819