Fix broken includes when compiling with builtin_miniupnpc=false

Fixes #99196
Supersedes #99218

modules/upnp/SCsub

@@ -35,6 +35,7 @@ if env["builtin_miniupnpc"] and env["platform"] != "web":
         env_upnp.Append(CPPDEFINES=["MINIUPNPC_SET_SOCKET_TIMEOUT"])
 
     env_thirdparty = env_upnp.Clone()
+    env_thirdparty.Prepend(CPPPATH=[thirdparty_dir + "include/miniupnpc"])
     env_thirdparty.disable_warnings()
     env_thirdparty.add_source_files(thirdparty_obj, thirdparty_sources)
     env.modules_sources += thirdparty_obj

modules/upnp/upnp_device_miniupnp.cpp

@@ -34,7 +34,7 @@
 
 #include "upnp_miniupnp.h"
 
-#include <upnpcommands.h>
+#include <miniupnpc/upnpcommands.h>
 
 void UPNPDeviceMiniUPNP::make_default() {
 	UPNPDevice::_create = UPNPDeviceMiniUPNP::_create;

modules/upnp/upnp_miniupnp.cpp

@@ -34,8 +34,8 @@
 
 #include "upnp_device_miniupnp.h"
 
-#include <miniwget.h>
-#include <upnpcommands.h>
+#include <miniupnpc/miniwget.h>
+#include <miniupnpc/upnpcommands.h>
 
 #include <stdlib.h>
 

modules/upnp/upnp_miniupnp.h

@@ -35,7 +35,7 @@
 
 #include "upnp.h"
 
-#include <miniupnpc.h>
+#include <miniupnpc/miniupnpc.h>
 
 class UPNPMiniUPNP : public UPNP {
 	GDCLASS(UPNPMiniUPNP, UPNP);

thirdparty/README.md

@@ -628,7 +628,8 @@ to solve some MSVC warnings. See the patches in the `patches` directory.
 
 Files extracted from upstream source:
 
-- Copy `miniupnpc/src` and `miniupnpc/include` to `thirdparty/miniupnpc`
+- `miniupnpc/src/` as `src/`
+- `miniupnpc/include/` as `include/miniupnpc/`
 - Remove the following test or sample files:
   `listdevices.c,minihttptestserver.c,miniupnpcmodule.c,upnpc.c,upnperrors.*,test*`
 - `LICENSE`