Update wii/gamecube configure
This patch updates the configure process for wii/gamecube builds using latest devkitPPC/libogc/libfat
I replaced the old powerpc-gekko host alias with the new powerpc-eabi alias
Under windows devkitPPC uses the TMP environment variable to find the temporary directory used for temp files generated when compiling. The configure script sets this variable during several tests which causes the tests to fail. I've replaced this variable with RES.
strings may not be available on windows if there's no native gcc in the path. Cross gcc provides <prefix>-strings so I've added a check for that in the endianness test.
backends/platform/wii/main.cpp used fatUnmountDefault which doesn't exist in official libfat, I've commented this out for now. I'll need to track down dhewg to see if it should be added.
With latest libogc, KEYBOARD_Init takes a parameter. I've patched this in backends/platform/wii/osystem_events.cpp
backends/platform/wii/wii.mk also needed patched with the new host alias.
Ticket imported from: #3109551. Ticket imported from: patches/1359.