Changes:
*) Make pth_poll(3) more compliant to POSIX.1-2001/SUSv3 poll(2).
*) Make pth_select(3) more compliant to POSIX.1-2001/SUSv3 select(2).
*) Replaced pth_event_occurred() with pth_event_status().
*) Add Autoconf option --with-fdsetsize=NUM for enlarging FD_SETSIZE.
*) Added thread attribute PTH_ATTR_DISPATCHES.
*) Added sub-API pth_uctx_* for user-space context switching.
*) Add a Pth variant of the new POSIX pselect(2) function.
*) Internally cleaned up the error handling macros.
*) Added POSIX-compliant sanity checks for bad fds.
*) Added pth_nanosleep() function.
*) Allow a NULL name for pth_msgport_create()
*) Completely rewrote the "hard syscall mapping".
*) Added support to pth_poll(3) for POLLD{RD,WR}{NORM,BAND}.
*) Fixed a long-standing termination bug in pth_exit(3).
*) Upgraded to Autoconf 2.57, Shtool 1.6.2 and Libtool 1.4.3.
*) Add optional support for OSSP ex based exception handling.
buildlink2.mk files back into the main trunk. This provides sufficient
buildlink2 infrastructure to start merging other packages from the
buildlink2 branch that have already been converted to use the buildlink2
framework.
