Do not preprocess src/Makefile.in.

Do not preprocess src/Makefile.in.

* configure.in: Do not preprocess src/Makefile.in.
(cpp_undefs, CPP_NEED_TRADITIONAL): Remove.
(AC_EGREP_CPP): Test no longer needed.
* configure: Regenerate.

* config.bat: Do not preprocess src/Makefile.in.

* make-dist: No more Makefile.c files.

* INSTALL, src/README: Makefiles are not preprocessed.

* src/Makefile.in, src/autodeps.mk, src/deps.mk, src/ns.mk:
Convert comments to Makefile format.

* lib-src/Makefile.in (distclean): No more Makefile.c.
* src/Makefile.in (bootstrap-clean): No more Makefile.c.

* admin/notes/cpp: Remove file.

* admin/quick-install-emacs (AVOID): No more Makefile.c files.

* etc/PROBLEMS, etc/MACHINES: Remove details of cpp problems which can
no longer occur.