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.