* configure.ac: Do not create links, only substitute the filenames.
* configure: Regenerate.
* Makefile.in: Assign the substitution results to variables.
(LIBGCC_LINKS): Define.
(enable-execute-stack.c): New rule.
(unwind.h): Likewise.
(md-unwind-support.h): Likewise.
(sfp-machine.h): Likewise.
(gthr-default.h): Likewise.
Add $(LIBGCC_LINKS) to the prerequisites of all object files and
unwind.h as prerequisite of install-unwind_h-forbuild.
From-SVN: r240312