o meta.c: move handling of .MAKE.META.IGNORE_* to meta_ignore()
	    so we can call it before adding entries to missingFiles.
	    Thus we do not track files we have been told to ignore.
	  o meta_oodate: apply .MAKE.META.IGNORE_FILTER (if defined) to
	    pathnames, and skip if the expansion is empty.
	    Useful for dirdeps.mk when checking DIRDEPS_CACHE.
	  o meta.c: remove all missingFiles entries that match a deleted
	    dir.
	  o main.c: set .ERROR_CMD if possible.