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/stdio/lib_fputs.c

@@ -0,0 +1,180 @@
+/****************************************************************************
+ * libs/libc/stdio/lib_fputs.c
+ *
+ *   Copyright (C) 2007, 2008, 2011-2012, 2017 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 <stdio.h>
+#include <string.h>
+#include <errno.h>
+
+#include <nuttx/arch.h>
+
+#include "libc.h"
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: fputs
+ *
+ * Description:
+ *   fputs() writes the string s to stream, without its trailing '\0'.
+ *
+ ****************************************************************************/
+
+#if defined(CONFIG_ARCH_ROMGETC)
+int fputs(FAR const char *s, FAR FILE *stream)
+{
+  int nput;
+  int ret;
+  char ch;
+
+  /* Make sure that a string was provided. */
+
+#ifdef CONFIG_DEBUG_FEATURES /* Most parameter checking is disabled if DEBUG is off */
+  if (!s)
+    {
+      set_errno(EINVAL);
+      return EOF;
+    }
+#endif
+
+  /* Write the string.  Loop until the null terminator is encountered */
+
+  for (nput = 0, ch = up_romgetc(s); ch; nput++, s++, ch = up_romgetc(s))
+    {
+      /* Write the next character to the stream buffer */
+
+      ret = lib_fwrite(&ch, 1, stream);
+      if (ret <= 0)
+        {
+          return EOF;
+        }
+
+      /* Flush the buffer if a newline was written to the buffer */
+
+      if (ch == '\n' && (stream->fs_flags & __FS_FLAG_LBF) != 0)
+        {
+          ret = lib_fflush(stream, true);
+          if (ret < 0)
+            {
+              return EOF;
+            }
+        }
+    }
+
+  return nput;
+}
+
+#else
+int fputs(FAR const char *s, FAR FILE *stream)
+{
+  int nput;
+
+  /* Make sure that a string was provided. */
+
+#ifdef CONFIG_DEBUG_FEATURES /* Most parameter checking is disabled if DEBUG is off */
+  if (s == NULL || stream == NULL)
+    {
+      set_errno(EINVAL);
+      return EOF;
+    }
+#endif
+
+  /* If line buffering is enabled, then we will have to output one character
+   * at a time, checking for a newline character each time.
+   */
+
+  if ((stream->fs_flags & __FS_FLAG_LBF) != 0)
+    {
+      int ret;
+
+      /* Write the string.  Loop until the null terminator is encountered */
+
+      for (nput = 0; *s; nput++, s++)
+        {
+          /* Write the next character to the stream buffer */
+
+          ret = lib_fwrite(s, 1, stream);
+          if (ret <= 0)
+            {
+              return EOF;
+            }
+
+          /* Flush the buffer if a newline was written to the buffer */
+
+          if (*s == '\n')
+            {
+              ret = lib_fflush(stream, true);
+              if (ret < 0)
+                {
+                  return EOF;
+                }
+            }
+        }
+    }
+
+  /* Without line buffering, we can write the whole string in one operation. */
+
+  else
+    {
+      int ntowrite;
+
+      /* Get the length of the string. */
+
+      ntowrite = strlen(s);
+      if (ntowrite == 0)
+        {
+          return 0;
+        }
+
+      /* Write the string */
+
+      nput = lib_fwrite(s, ntowrite, stream);
+      if (nput < 0)
+        {
+          return EOF;
+        }
+
+    }
+
+  return nput;
+}
+#endif