* configure.in (LIBMUDFLAPTH):  Fix thinko.

	* configure.in:  Check for more headers.
	* mf-hooks2.c:  Conditionalize on HAVE_SYS_SOCKET_H etc.

	* mf-runtime.c:  In two places conditionalize on SIUSR1 rather than
	HAVE_SIGNAL as mingw has signal.h but not SIUSR1.

From-SVN: r82627