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, 57 insertions, 0 deletions

diff --git a/lib/krb4.h b/lib/krb4.h
new file mode 100644
index 000000000..3e29b2588
--- /dev/null
+++ b/lib/krb4.h
@@ -0,0 +1,57 @@
+#ifndef HEADER_CURL_KRB4_H
+#define HEADER_CURL_KRB4_H
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1998 - 2011, 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.
+ *
+ ***************************************************************************/
+
+struct Curl_sec_client_mech {
+  const char *name;
+  size_t size;
+  int (*init)(void *);
+  int (*auth)(void *, struct connectdata *);
+  void (*end)(void *);
+  int (*check_prot)(void *, int);
+  int (*overhead)(void *, int, int);
+  int (*encode)(void *, const void*, int, int, void**, struct connectdata *);
+  int (*decode)(void *, void*, int, int, struct connectdata *);
+};
+
+
+#define AUTH_OK         0
+#define AUTH_CONTINUE   1
+#define AUTH_ERROR      2
+
+#ifdef HAVE_KRB4
+extern struct Curl_sec_client_mech Curl_krb4_client_mech;
+#endif
+#ifdef HAVE_GSSAPI
+extern struct Curl_sec_client_mech Curl_krb5_client_mech;
+#endif
+
+CURLcode Curl_krb_kauth(struct connectdata *conn);
+int Curl_sec_read_msg (struct connectdata *conn, char *,
+                       enum protection_level);
+void Curl_sec_end (struct connectdata *);
+CURLcode Curl_sec_login (struct connectdata *);
+int Curl_sec_request_prot (struct connectdata *conn, const char *level);
+
+#endif /* HEADER_CURL_KRB4_H */
+