property_get: do argument checking.

Try to verify, at compile time, that the supplied
value buffer is large enough.

Change-Id: I91fa560d3ceff87609194269356ac634bdbf2ede

Conflicts:
	include/cutils/properties.h
Don't use __attribute__(__error__)

__attribute(__error__) isn't supported on clang, and generates
compiler warnings. Use __errordecl instead, which does the right thing
for different compilers.

Change-Id: Ifb0797a5de703cc5b3c39dcd97bcfaf404f1cafa