Revert changes relative to lib/*.[ch] recent renaming

This reverts renaming and usage of lib/*.h header files done
28-12-2012, reverting 2 commits:

  f871de0... build: make use of 76 lib/*.h renamed files
  ffd8e12... build: rename 76 lib/*.h files

This also reverts removal of redundant include guard (redundant thanks
to changes in above commits) done 2-12-2013, reverting 1 commit:

  c087374... curl_setup.h: remove redundant include guard

This also reverts renaming and usage of lib/*.c source files done
3-12-2013, reverting 3 commits:

  13606bb... build: make use of 93 lib/*.c renamed files
  5b6e792... build: rename 93 lib/*.c files
  7d83dff... build: commit 13606bbfde follow-up 1

Start of related discussion thread:

  http://curl.haxx.se/mail/lib-2013-01/0012.html

Asking for confirmation on pushing this revertion commit:

  http://curl.haxx.se/mail/lib-2013-01/0048.html

Confirmation summary:

  http://curl.haxx.se/mail/lib-2013-01/0079.html

NOTICE: The list of 2 files that have been modified by other
intermixed commits, while renamed, and also by at least one
of the 6 commits this one reverts follows below. These 2 files
will exhibit a hole in history unless git's '--follow' option
is used when viewing logs.

  lib/curl_imap.h
  lib/curl_smtp.h

1 files changed, 66 insertions, 0 deletions

diff --git a/lib/strtok.c b/lib/strtok.c
new file mode 100644
index 000000000..94eac0e64
--- /dev/null
+++ b/lib/strtok.c
@@ -0,0 +1,66 @@
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1998 - 2007, Daniel Stenberg, <daniel@haxx.se>, et al.
+ *
+ * This software is licensed as described in the file COPYING, which
+ * you should have received as part of this distribution. The terms
+ * are also available at http://curl.haxx.se/docs/copyright.html.
+ *
+ * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+ * copies of the Software, and permit persons to whom the Software is
+ * furnished to do so, under the terms of the COPYING file.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ***************************************************************************/
+
+#include "setup.h"
+
+#ifndef HAVE_STRTOK_R
+#include <stddef.h>
+
+#include "strtok.h"
+
+char *
+Curl_strtok_r(char *ptr, const char *sep, char **end)
+{
+  if(!ptr)
+    /* we got NULL input so then we get our last position instead */
+    ptr = *end;
+
+  /* pass all letters that are including in the separator string */
+  while(*ptr && strchr(sep, *ptr))
+    ++ptr;
+
+  if(*ptr) {
+    /* so this is where the next piece of string starts */
+    char *start = ptr;
+
+    /* set the end pointer to the first byte after the start */
+    *end = start + 1;
+
+    /* scan through the string to find where it ends, it ends on a
+       null byte or a character that exists in the separator string */
+    while(**end && !strchr(sep, **end))
+      ++*end;
+
+    if(**end) {
+      /* the end is not a null byte */
+      **end = '\0';  /* zero terminate it! */
+      ++*end;        /* advance the last pointer to beyond the null byte */
+    }
+
+    return start; /* return the position where the string starts */
+  }
+
+  /* we ended up on a null byte, there are no more strings to find! */
+  return NULL;
+}
+
+#endif /* this was only compiled if strtok_r wasn't present */