uniaud: fix -Zhigh-mem problem

Uniaud does not work with the buffer allocated in high memory.
Makefile: add -Zhigh-mem linker flag for kLIBC target
kaidemo2: missing #include for OpenWatom C/C++
Show error messages only if KAIDEBUG is set
kLIBC: missing #include for _lmalloc() and _lcalloc()
uniaud: remove unnecessary DosSleep()