curl tool: use configuration files from lib directory

Configuration files such as curl_config.h and all config-*.h no longer exist
nor are generated/copied into 'src' directory, now these only exist in 'lib'
directory from where curl tool sources uses them.

Additionally old src/setup.h has been refactored into src/tool_setup.h which
now pulls lib/setup.h

The possibility of a makefile needing an include path adjustment exists.

src/tool_formparse.c

@@ -19,7 +19,7 @@
  * KIND, either express or implied.
  *
  ***************************************************************************/
-#include "setup.h"
+#include "tool_setup.h"
 
 #include <curl/curl.h>