Import 0.12.5 vendor code.
Merge branch 'vendor' to bring in 0.12.5 code.

Conflicts:
	.gitignore
	Makefile
	Makefile.target
	audio/audio_int.h
	block/raw-posix.c
	configure
	cpu-exec.c
	fpu/softfloat-native.h
	kqemu.c
	kqemu.h
	net.c
	osdep.c
	vl.c
Disable pthread check on Haiku as it is always available.
Remove now redundant CONFIG_HAIKU defines.
Port Haiku audio driver to 0.12.5 API.
Add empty tap-haiku stub implementation.
Remove now unsupported kqemu.