pge ebnf and def2doc.py first cut complete for Sphinx

pge ebnf and def2doc.py first cut complete for Sphinx

The m2 tools have been changed to emit Sphinx output.
pge has also been rebuilt.

gcc/m2/ChangeLog:

	* gcc/m2/Make-lang.in: Introduced rst rules for
	subcomponents: gm2-libs.rst, gm2-ebnf.rst
	SYSTEM-pim.rst, SYSTEM-iso.rst and Builtins.rst.
	* gcc/m2/Make-maintainer.in: Added pge-clean rule.
	* gcc/m2/gm2-compiler/ppg.mod: Introduced new option
	-x for sphinx output.  Implemented ebnf pretty printing.
	* gcc/m2/tools-src/def2doc.py: Introduced state class
	to ensure that the rst block is only changed if
	necessary.
	* gcc/m2/pge-boot/GASCII.c: Rebuilt.
	* gcc/m2/pge-boot/GArgs.c: Rebuilt.
	* gcc/m2/pge-boot/GAssertion.c: Rebuilt.
	* gcc/m2/pge-boot/GDebug.c: Rebuilt.
	* gcc/m2/pge-boot/GDynamicStrings.c: Rebuilt.
	* gcc/m2/pge-boot/GFIO.c: Rebuilt.
	* gcc/m2/pge-boot/GIO.c: Rebuilt.
	* gcc/m2/pge-boot/GIndexing.c: Rebuilt.
	* gcc/m2/pge-boot/GLists.c: Rebuilt.
	* gcc/m2/pge-boot/GM2Dependent.c: Rebuilt.
	* gcc/m2/pge-boot/GM2EXCEPTION.c: Rebuilt.
	* gcc/m2/pge-boot/GM2RTS.c: Rebuilt.
	* gcc/m2/pge-boot/GNameKey.c: Rebuilt.
	* gcc/m2/pge-boot/GNumberIO.c: Rebuilt.
	* gcc/m2/pge-boot/GOutput.c: Rebuilt.
	* gcc/m2/pge-boot/GPushBackInput.c: Rebuilt.
	* gcc/m2/pge-boot/GRTExceptions.c: Rebuilt.
	* gcc/m2/pge-boot/GSFIO.c: Rebuilt.
	* gcc/m2/pge-boot/GStdIO.c: Rebuilt.
	* gcc/m2/pge-boot/GStorage.c: Rebuilt.
	* gcc/m2/pge-boot/GStrCase.c: Rebuilt.
	* gcc/m2/pge-boot/GStrIO.c: Rebuilt.
	* gcc/m2/pge-boot/GStrLib.c: Rebuilt.
	* gcc/m2/pge-boot/GSymbolKey.c: Rebuilt.
	* gcc/m2/pge-boot/GSysStorage.c: Rebuilt.
	* gcc/m2/pge-boot/Gbnflex.c: Rebuilt.
	* gcc/m2/pge-boot/Gpge.c: Rebuilt.
	* gcc/m2/pge-boot/main.c: Rebuilt.

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