2009-09-10 Ivan Maidanski <ivmai@mail.ru>

2009-09-10  Ivan Maidanski <ivmai@mail.ru>
	(diff118_cvs - superseding diff53)

	* allchblk.c (MUNMAP_THRESHOLD): Move macro definition out of
	a function.
	* allchblk.c (GC_unmap_threshold): New global variable definition
	(initialized to MUNMAP_THRESHOLD).
	* allchblk.c (GC_unmap_old): Use GC_unmap_threshold instead of
	MUNMAP_THRESHOLD; skip unmapping if GC_unmap_threshold is 0.
	* doc/README.environment (GC_UNMAP_THRESHOLD): Add information.
	* misc.c (GC_unmap_threshold): New variable declaration.
	* misc.c (GC_init_inner): Recognize "GC_UNMAP_THRESHOLD"
	environment variable to set GC_unmap_threshold value (only if
	USE_MUNMAP).