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

76 private header files renamed to use our standard naming scheme.

This change affects 322 files in libcurl's source tree.

lib/setup.h

@@ -645,8 +645,8 @@ int netware_init(void);
  * Include macros and defines that should only be processed once.
  */
 
-#ifndef __SETUP_ONCE_H
-#include "setup_once.h"
+#ifndef HEADER_CURL_SETUP_ONCE_H
+#include "curl_setup_once.h"
 #endif
 
 /*