This commit moves all of the libraries under a common directory called libs/. This most certainly break libcxx and uClibc++ for now.

Squashed commit of the following:

    libs/libxx:  Fix some confusing in naming.  If the directory is called libxx, then the library must be libxx.a (unless perhaps LIBCXX is selected).
    libs/:  Fix paths in moved library directories.
    libs:  Brute force move of libc, libnx, and libxx to libs.  Cannot yet build it in that configuration.

libs/libc/time/lib_gettimeofday.c

@@ -0,0 +1,98 @@
+/****************************************************************************
+ * libs/libc/time/lib_gettimeofday.c
+ *
+ *   Copyright (C) 2009, 2015 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.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <sys/time.h>
+#include <errno.h>
+
+#include <nuttx/clock.h>
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: gettimeofday
+ *
+ * Description:
+ *   Get the current time
+ *
+ *   Conforming to SVr4, 4.3BSD. POSIX.1-2001 describes gettimeofday().
+ *   POSIX.1-2008 marks gettimeofday() as obsolete, recommending the use of
+ *   clock_gettime(2) instead.
+ *
+ *   NuttX implements gettimeofday() as a thin layer around clock_gettime();
+ *
+ * Input Parameters:
+ *   tv - The location to return the current time
+ *   tz - Ignored
+ *
+ * Returned Value:
+ *   Zero (OK) on success;  -1 is returned on failure with the errno variable
+ *   set appropriately.
+ *
+ ****************************************************************************/
+
+int gettimeofday(FAR struct timeval *tv, FAR struct timezone *tz)
+{
+  struct timespec ts;
+  int ret;
+
+#ifdef CONFIG_DEBUG_FEATURES
+  if (!tv)
+    {
+      set_errno(EINVAL);
+      return ERROR;
+    }
+#endif
+
+  /* Let clock_gettime do most of the work */
+
+  ret = clock_gettime(CLOCK_REALTIME, &ts);
+  if (ret == OK)
+    {
+       /* Convert the struct timespec to a struct timeval */
+
+       tv->tv_sec  = ts.tv_sec;
+       tv->tv_usec = ts.tv_nsec / NSEC_PER_USEC;
+    }
+
+  return ret;
+}