Include cstdint

to make it compile on openSUSE Tumbleweed's gcc15

Without this, it did not find definitions for uint32_t etc

Author: bmwiedemann

src/net/net.hpp

@@ -1,4 +1,5 @@
 #pragma once
+#include <cstdint>
 #include "../fwd.hpp"
 
 namespace PanzerChasm

src/rendering_context.hpp

@@ -1,4 +1,5 @@
 #pragma once
+#include <cstdint>
 #include <memory>
 
 #include <shaders_loading.hpp>