Remove src/Makefile.am.

Remove src/Makefile.am.

	* src/Makefile.am: Rename as...
	* src/local.mk: this.
	Prefix all the paths with src/.
	(AUTOMAKE_OPTIONS): Build object files in the sub dirs.
	(AM_CPPFLAGS): Find find in builddir/src.
	(YACC): Move the flags into...
	(AM_YFLAGS): here.
	* maint.mk (sc_tight_scope): Disable.
	It used to bounce to the version in src/Makefile.am which is now
	part of this very Makefile.
	* Makefile.am, configure.ac: Adjust.
	* src/scan-code-c.c, src/scan-code.l: We can no longer rely on
	include "..." to find files "here": we are no longer in src/, so
	qualify the includes with src/.
	* doc/Makefile.am (PREPATH): No longer include the top_builddir
	prefix.
	(.x.1): Adjust to be able to create src/foo from the top level
	Makefile, instead of going bounce to src/Makefile the creation of
	foo.