Remove the non-maintained CMake build system.

It is difficult to maintain one build system, let alone two - especially
if one build system is known to be better maintained and the other build
system continues to be used - with bug and feature requests raised
against it.

The maintainers are aware that there are people using the CMake system,
but believe that the extra maintainability of only having one build
system, combined with the knowledge that the current CI system
demonstrates that all supported architectures are working with the
Makefiles make the use of these Makefiles a more sustainable direction.

include/n2n.h

@@ -38,21 +38,14 @@
 
 /* #define N2N_CAN_NAME_IFACE */
 
+#include "config.h" /* Visual C++ */
+
 /* Moved here to define _CRT_SECURE_NO_WARNINGS before all the including takes place */
 #ifdef WIN32
-#ifndef CMAKE_BUILD
-#include "config.h" /* Visual C++ */
-#else
-#include "winconfig.h"
-#endif
 #define N2N_CAN_NAME_IFACE 1
 #undef N2N_HAVE_DAEMON
 #undef N2N_HAVE_TCP           /* as explained on https://github.com/ntop/n2n/pull/627#issuecomment-782093706 */
 #undef N2N_HAVE_SETUID
-#else
-#ifndef CMAKE_BUILD
-#include "config.h"
-#endif
 #endif
 
 

include/n2n_port_mapping.h

@@ -24,17 +24,9 @@
 #include <stdint.h>
 
 #ifdef HAVE_MINIUPNP
-#ifdef CMAKE_BUILD
-// CMAKE uses statically linked lib as submodule which requires different includes than
-//       the dynamically linked, intalled library in case of plain make
-#include <miniupnpc.h>
-#include <upnpcommands.h>
-#include <upnperrors.h>
-#else
 #include <miniupnpc/miniupnpc.h>
 #include <miniupnpc/upnpcommands.h>
 #include <miniupnpc/upnperrors.h>
-#endif // CMAKE_BUILD
 #endif // HAVE_MINIUPNP