This is a follow-up patch to
THRIFT-1490. The previous code would never follow the Windows XP path (WINVER 0x0501). At least that appears to be the case since poll_win32() was incomplete and not functional. Windows' version of select() does not set the revents field so FD_ISSET is used to determine how to manually set it. I've tested this on a sample project and it's working as expected. config.h is now targeting XP for wider compatibility. If this isn't desired or you don't trust the new code, comment out the two #define lines toward the top and it will revert to targeting Vista/Win7.