geode-optimized glibc routines

[Rob Savoye]

Andrew Burgess wrote:

> since the code refers to the cpu instruction set rather than the motherboard.

  That's what my current changes do, they pass in -march=geode
-mtune=geode by default when compiling. The native GCC for the X0 does
this too. I only added it this way so it works as a cross compiler too.
Optimizing glib is basically replacing the low level string and memory
routines with ones tuned for the Geode GX.

	- rob -