srcextra fixes

srcextra fixes

Here is a patch which uses sed to fix up the copies of the generated
files by flex/bison in the source directories (i.e. what we ship in
release tarballs).
In that case the generated files are in the same directory as the
files they are generated from, so there should be no absolute or relative
directories, just the filenames.

Furthermore, c.srcextra was duplicating the work of gcc.srcextra, there is
nothing C FE specific on gengtype-lex.l.

2025-03-28  Jakub Jelinek  <jakub@redhat.com>

gcc/
	* Makefile.in (gcc.srcextra): Use sed to turn .../gcc/gengtype-lex.l
	in #line directives into just gengtype-lex.l.
gcc/c/
	* Make-lang.in (c.srcextra): Don't depend on anything and don't copy
	anything.
gcc/cobol/
	* Make-lang.in (cobol.srcextra): Use sed to turn
	.../gcc/cobol/*.{y,l,h,cc} and cobol/*.{y,l,h,cc} in #line directives
	into just *.{y,l,h,cc}.