* include/gc.h (GC_INIT): Add DATASTART and DATAEND roots on AIX.
	* include/private/gcconfig.h (RS6000): Add 64-bit AIX support.
	Define USE_GENERIC_PUSH_REGS.  Use AIX _data and _end symbols for
	DATASTART and DATAEND roots.
	* rs6000_mach_dep.s: Add function descriptor and traceback table.

From-SVN: r49218