PR-108135 Modula2 meets clang (remove dead code and bugfix m2.flex)

These patches fix warnings (and a bug) discovered by clang. The
patch set looks longer than the changes as pge and mc needed to be
rebuilt (due to a change in the gcc/m2/gm2-libs/DynamicString.mod
library).

gcc/m2/ChangeLog:

	* gm2-gcc/m2statement.cc (gm2_gimplify_function_node):
	Remove.
	* gm2-libs/DynamicStrings.mod (Equal): Remove dead code.
	* m2.flex (<COMMENT>"<*"): Add {} for else statement.
	* m2pp.cc (hextree): Add conditional #ifdef DEBUGGING.
	* mc-boot/GDynamicStrings.c: Rebuild.
	* pge-boot/GDynamicStrings.c: Rebuild.
	* pge-boot/GFIO.c: Rebuild.
	* pge-boot/GIndexing.c: Rebuild.
	* pge-boot/GM2EXCEPTION.c: Rebuild.
	* pge-boot/GM2RTS.c: Rebuild.
	* pge-boot/GNameKey.c: Rebuild.
	* pge-boot/GPushBackInput.c: Rebuild.
	* pge-boot/GRTExceptions.c: Rebuild.
	* pge-boot/GStdIO.c: Rebuild.
	* pge-boot/GSymbolKey.c: Rebuild.
	* pge-boot/GSysStorage.c: Rebuild.

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