Add build support for messages queues as part of the VFS (only build logic, no C files yet)

fs/Makefile

@@ -52,6 +52,7 @@ include mmap/Make.defs
 # OS resources
 
 include semaphore/Make.defs
+include mqueue/Make.defs
 
 # Additional files required is mount-able file systems are supported
 

fs/mqueue/Kconfig

@@ -0,0 +1,7 @@
+#
+# For a description of the syntax of this configuration file,
+# see misc/tools/kconfig-language.txt.
+#
+
+if !DISABLE_MQUEUE
+endif # !DISABLE_MQUEUE

fs/mqueue/Make.defs

@@ -0,0 +1,46 @@
+############################################################################
+# fs/mqueue/Make.defs
+#
+#   Copyright (C) 2014 Gregory Nutt. All rights reserved.
+#   Author: Gregory Nutt <gnutt@nuttx.org>
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+#
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in
+#    the documentation and/or other materials provided with the
+#    distribution.
+# 3. Neither the name NuttX nor the names of its contributors may be
+#    used to endorse or promote products derived from this software
+#    without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+# FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+# COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+# OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+# AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+#
+############################################################################
+
+# Include POSIX message queue support
+
+ifneq ($(CONFIG_DISABLE_MQUEUE),y)
+
+#CSRCS +=
+
+# Include POSIX message queue build support
+
+DEPPATH += --dep-path mqueue
+VPATH += :mqueue
+endif

fs/semaphore/sem_unlink.c

@@ -152,6 +152,7 @@ int sem_unlink(FAR const char *name)
    */
 
   DEBUGASSERT(ret >= 0 || ret == -EBUSY);
+  UNUSED(ret);
 
   /* Now we do not release the reference count in the normal way (by calling
    * inode release.  Rather, we call sem_close().  sem_close will decrement