* configure.in: Remove NO_GETENV definition for win32.
	* mach_dep.c (GC_generic_push_regs): Prevent tail call optimization.
	* misc.c (GC_init_inner): Call GC_thr_init for win32.
	  (GC_set_warn_proc): Add assertion.
	* win32_threads.c: Import 6.3alpha2 version.
	* include/private/gc_priv.h: Add support for EMPTY_GETENV_RESULTS.

From-SVN: r72074