Haiku does not yet support certain features related to POSIX threads.
Constants used to test for the presence of these features should
therefore be left undefined, according to the POSIX spec, but are
currently set to -1. This can cause software built on Haiku to
incorrectly detect the presence of these features.
* unistd.h: Undefine _POSIX_THREAD_ATTR_STACKADDR,
_POSIX_THREAD_PRIORITY_SCHEDULING feature constants.
* conf.cpp: __sysconf: Return -1 for unsupported features.
Signed-off-by: Augustin Cavalier <[email protected]>