* Makefile.in (DLL_OFILES): Add posix_ipc.o.

* cygwin.din (mq_close): Export.
	(mq_getattr): Export.
	(mq_notify): Export.
	(mq_open): Export.
	(mq_receive): Export.
	(mq_send): Export.
	(mq_setattr): Export.
	(mq_timedreceive): Export.
	(mq_timedsend): Export.
	(mq_unlink): Export.
	* posix_ipc.cc: New file implementing the above functions.  Move
	shm_open and shm_unlink from syscalls.cc here.
	* sysconf.cc (sca): Set value of _SC_MQ_OPEN_MAX to MQ_OPEN_MAX,
	_SC_MQ_PRIO_MAX to MQ_PRIO_MAX, _SC_MESSAGE_PASSING to
	_POSIX_MESSAGE_PASSING.
	* include/limits.h (MQ_OPEN_MAX): Define.
	(MQ_PRIO_MAX): Define.
	* include/mqueue.h: New file.
	* include/cygwin/version.h: Bump API minor number.

winsup/cygwin/include/mqueue.h

@@ -0,0 +1,45 @@
+/* mqueue.h: POSIX message queue interface
+
+   Copyright 2007 Red Hat, Inc.
+
+   This file is part of Cygwin.
+
+   This software is a copyrighted work licensed under the terms of the
+   Cygwin license.  Please consult the file "CYGWIN_LICENSE" for
+   details. */
+
+#include <time.h>
+#include <sys/types.h>
+#include <sys/signal.h>
+#include <sys/cdefs.h>
+
+#ifndef _MQUEUE_H
+#define _MQUEUE_H
+
+__BEGIN_DECLS
+
+typedef void *mqd_t;
+
+struct mq_attr {
+  long  mq_flags;	/* Message queue flags */
+  long  mq_maxmsg;	/* Max number of messages in queue */
+  long  mq_msgsize;	/* Max message size */
+  long  mq_curmsgs;	/* Current number of messages in queue */
+};
+
+int     mq_close (mqd_t);
+int     mq_getattr (mqd_t, struct mq_attr *);
+int     mq_notify (mqd_t, const struct sigevent *);
+mqd_t   mq_open (const char *, int, ...);
+ssize_t mq_receive (mqd_t, char *, size_t, unsigned int *);
+int     mq_send (mqd_t, const char *, size_t, unsigned int);
+int     mq_setattr (mqd_t, const struct mq_attr *, struct mq_attr *);
+ssize_t mq_timedreceive (mqd_t, char *, size_t, unsigned int *,
+			 const struct timespec *);
+int     mq_timedsend (mqd_t, const char *, size_t, unsigned int,
+		      const struct timespec *);
+int     mq_unlink (const char *name);
+
+__END_DECLS
+
+#endif /* _MQUEUE_H */