PR modula2/118703 Abort compiling m2pim_NumberIO_BinToStr

This patch builds access to the gcc builtins clz, clzl, clzll,
ctz, ctzl and ctzll within m2builtins.cc.  The patch provides
modula2 api access to clz, clzll, ctz and ctzll though the
Builtins definition module.  This PR was raised because of
PR118689.

gcc/m2/ChangeLog:

	PR modula2/118703
	* gm2-gcc/m2builtins.cc (define_builtin_gcc): New function.
	(m2builtins_init): Call define_builtin_gcc.
	* gm2-libs/Builtins.def (clz): New procedure function.
	(clzll): Ditto.
	(ctz): Ditto.
	(ctzll): Ditto.
	* gm2-libs/Builtins.mod (clz): New procedure function.
	(clzll): Ditto.
	(ctz): Ditto.
	(ctzll): Ditto.
	* gm2-libs/cbuiltin.def (clz): New procedure function.
	(clzll): Ditto.
	(ctz): Ditto.
	(ctzll): Ditto.

gcc/testsuite/ChangeLog:

	PR modula2/118703
	* gm2/builtins/run/pass/testbitfns.mod: New test.

Signed-off-by: Gaius Mulley <gaiusmod2@gmail.com>