match.pd: Use splits in makefile and make configurable.

match.pd: Use splits in makefile and make configurable.

This updates the build system to split up match.pd files into chunks of 10.
This also introduces a new flag --with-matchpd-partitions which can be used to
change the number of partitions.

For the analysis of why 10 please look at the previous patch in the series.

gcc/ChangeLog:

	PR bootstrap/84402
	* Makefile.in (NUM_MATCH_SPLITS, MATCH_SPLITS_SEQ,
	GIMPLE_MATCH_PD_SEQ_SRC, GIMPLE_MATCH_PD_SEQ_O,
	GENERIC_MATCH_PD_SEQ_SRC, GENERIC_MATCH_PD_SEQ_O): New.
	(OBJS, MOSTLYCLEANFILES, .PRECIOUS): Use them.
	(s-match): Split into s-generic-match and s-gimple-match.
	* configure.ac (with-matchpd-partitions,
	DEFAULT_MATCHPD_PARTITIONS): New.
	* configure: Regenerate.