diff: Linux/PPC global reg variable changes

[Fergus Henderson]

Add support for gcc global registers on Linux/PPC.

runtime/mercury_regs.h:
	Change `#if defined(_POWER)' to
	`#if defined(_POWER) || defined(__powerpc)',
	since gcc on Linux/PPC does not defined `_POWER'.

runtime/machdeps/rs6000_regs.h:
	Fix a typo that broke the PPC port:
	`restore_transient_reg_from_mem' should have been
	`restore_transient_regs_from_mem'.
			      ^
README.Linux-PPC:
	Update to reflect recent developments: with egcs,
	we now support global register variables.

-- 
Fergus Henderson <fjh at cs.mu.oz.au>   |  "I have always known that the pursuit
WWW: <http://www.cs.mu.oz.au/~fjh>   |  of excellence is a lethal habit"
PGP: finger fjh at 128.250.37.3         |     -- the last words of T. S. Garp.