Don't compile in null sound driver for libretro and add
Makefile.libretro
Changes to Makefile.libretro
Add support for PlayBook/BB10 with libretro
Add missing ifdef, move QNX RAM mapping closer to others
use gas-preprocessor for ios

imported from https://github.com/yuvi/gas-preprocessor
gte: be friendly to more assemblers
gas-preprocessor: support .bss

same as .data on Mach-O it seems
cspace_neon: convert to .S

we'll need the preprocessor in next patch
asm: use a macro for functions
libretro: rework makefile