xrick: Fix various errors/warnings
* Piles of warnings in miniz when built with modern toolchain
* Pointer arithematic error in PRNG
* Casting between int and void * for file descriptors
* Warning on non-color targets
Remaining:
* Failure on XRGB888 LCDs due to issue with core LCD macros
* Failure on interleaved greyscale LCDs (?)
* HTML manual build failure
Change-Id: Ibf6d2c001ec8daf583731d5da15b86b5352773e7