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

lib/hostcheck.c

@@ -0,0 +1,96 @@
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1998 - 2012, 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"
+
+#if defined(USE_SSLEAY) || defined(USE_AXTLS)
+/* these two backends use functions from this file */
+
+#include "hostcheck.h"
+#include "rawstr.h"
+
+/*
+ * Match a hostname against a wildcard pattern.
+ * E.g.
+ *  "foo.host.com" matches "*.host.com".
+ *
+ * We use the matching rule described in RFC6125, section 6.4.3.
+ * http://tools.ietf.org/html/rfc6125#section-6.4.3
+ */
+
+static int hostmatch(const char *hostname, const char *pattern)
+{
+  const char *pattern_label_end, *pattern_wildcard, *hostname_label_end;
+  int wildcard_enabled;
+  size_t prefixlen, suffixlen;
+  pattern_wildcard = strchr(pattern, '*');
+  if(pattern_wildcard == NULL)
+    return Curl_raw_equal(pattern, hostname) ?
+      CURL_HOST_MATCH : CURL_HOST_NOMATCH;
+
+  /* We require at least 2 dots in pattern to avoid too wide wildcard
+     match. */
+  wildcard_enabled = 1;
+  pattern_label_end = strchr(pattern, '.');
+  if(pattern_label_end == NULL || strchr(pattern_label_end+1, '.') == NULL ||
+     pattern_wildcard > pattern_label_end ||
+     Curl_raw_nequal(pattern, "xn--", 4)) {
+    wildcard_enabled = 0;
+  }
+  if(!wildcard_enabled)
+    return Curl_raw_equal(pattern, hostname) ?
+      CURL_HOST_MATCH : CURL_HOST_NOMATCH;
+
+  hostname_label_end = strchr(hostname, '.');
+  if(hostname_label_end == NULL ||
+     !Curl_raw_equal(pattern_label_end, hostname_label_end))
+    return CURL_HOST_NOMATCH;
+
+  /* The wildcard must match at least one character, so the left-most
+     label of the hostname is at least as large as the left-most label
+     of the pattern. */
+  if(hostname_label_end - hostname < pattern_label_end - pattern)
+    return CURL_HOST_NOMATCH;
+
+  prefixlen = pattern_wildcard - pattern;
+  suffixlen = pattern_label_end - (pattern_wildcard+1);
+  return Curl_raw_nequal(pattern, hostname, prefixlen) &&
+    Curl_raw_nequal(pattern_wildcard+1, hostname_label_end - suffixlen,
+                    suffixlen) ?
+    CURL_HOST_MATCH : CURL_HOST_NOMATCH;
+}
+
+int Curl_cert_hostcheck(const char *match_pattern, const char *hostname)
+{
+  if(!match_pattern || !*match_pattern ||
+      !hostname || !*hostname) /* sanity check */
+    return 0;
+
+  if(Curl_raw_equal(hostname, match_pattern)) /* trivial case */
+    return 1;
+
+  if(hostmatch(hostname,match_pattern) == CURL_HOST_MATCH)
+    return 1;
+  return 0;
+}
+
+#endif /* SSLEAY or AXTLS */