a bit more -Werror compatability

for clang, fix warnings in drivers/, lib/, servers/, sys/, common/.
by turning off fatal warnings (takes effect if the default is on),
fixing warnings or reducing the warning level.

Change-Id: Ia1b4bc877c879ba783158081b59aa6ebb021a50f
libminixfs: allow non-page-multiple blocksizes

	. this is OK (although it wastes some memory) as
	  long as the VM interface isn't used, which has its
	  own checks in libsys

Change-Id: I28decd367b2cd5c01482bdc71615c65ab61c9a71
libaudiodriver: allocate mem lower 16 MB and 64K aligned

Righ now, the DMA controller will access some random memory below 16 MB,
as the physical address returned by alloc_contig() is simply truncated
when given to the DMA controller.

Yes, it's bad...
sb16: Don't confuse pv_set()

Change-Id: Ib7b528aa3a369b54dda3bbceb498db4a600c4cb4
libaudiodriver: handle interrupt only once

Apparently, qemu's sb16 doesn't reset the interrupt register
of the mixer and the driver ends up in an endless loop when
playing a "multi-fragment" sample.

Change-Id: I47633b99a0d79ba201aec785da69fb3950e026bf
arm-build:force sfdisk to format like we want it.

Change-Id: Iaa3c994a30bb3df6129e85e0a5591b88b5b93973