* doc/invoke.texi (ggc-min-expand, ggc-min-heapsize): Document
	new default behavior.
	* ggc-common.c: Include sys/resource.h.
	(ggc_rlimit_bound): New function.
	(ggc_min_expand_heuristic, ggc_min_heapsize_heuristic): Update
	defaults to account for rlimits.

From-SVN: r63323