diff --git a/CMakeLists.txt b/CMakeLists.txt
index 851e11add9e85..cf8767121676f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -50,6 +50,7 @@ include(CheckIncludeFiles)
 include(CheckLanguage)
 include(CheckSymbolExists)
 include(CheckCSourceCompiles)
+include(CheckCXXSourceCompiles)
 include(CheckCSourceRuns)
 include(CheckCCompilerFlag)
 include(CheckCXXCompilerFlag)
@@ -2314,7 +2315,7 @@ elseif(WINDOWS)
     static __x_ABI_CWindows_CGaming_CInput_CIGamepadStatics2 *s2;
     int main(int argc, char **argv) { return 0; }" HAVE_WINDOWS_GAMING_INPUT_H
   )
-  check_c_source_compiles("
+  check_cxx_source_compiles("
     #include <stdbool.h>
     #define COBJMACROS
     #include <gameinput.h>
diff --git a/include/SDL3/SDL_stdinc.h b/include/SDL3/SDL_stdinc.h
index 3e2266dc8f65a..893f2052f7dc2 100644
--- a/include/SDL3/SDL_stdinc.h
+++ b/include/SDL3/SDL_stdinc.h
@@ -256,7 +256,7 @@ void *alloca(size_t);
 #define SDL_arraysize(array) (sizeof(array)/sizeof(array[0]))  /* or `_Countof(array)` on recent gcc and clang */
 
 #else
-#if (defined(__GNUC__) && __GNUC__ >= 16) || SDL_HAS_EXTENSION(c_countof)
+#if !defined(__cplusplus) && ((defined(__GNUC__) && __GNUC__ >= 16) || SDL_HAS_EXTENSION(c_countof))
 #define SDL_arraysize(array) _Countof(array)
 #else
 #define SDL_arraysize(array) (sizeof(array)/sizeof(array[0]))
diff --git a/src/core/windows/SDL_gameinput.h b/src/core/windows/SDL_gameinput.h
index 0d7b6f85e74de..d283831ff14e1 100644
--- a/src/core/windows/SDL_gameinput.h
+++ b/src/core/windows/SDL_gameinput.h
@@ -25,8 +25,17 @@
 
 #ifdef HAVE_GAMEINPUT_H
 
+#ifdef HAVE_GCC_DIAGNOSTIC_PRAGMA
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wundef"
+#endif
+
 #include <gameinput.h>
 
+#ifdef HAVE_GCC_DIAGNOSTIC_PRAGMA
+#pragma GCC diagnostic pop
+#endif
+
 #ifndef GAMEINPUT_API_VERSION
 #define GAMEINPUT_API_VERSION 0
 #endif
diff --git a/src/joystick/gdk/SDL_gameinputjoystick.cpp b/src/joystick/gdk/SDL_gameinputjoystick.cpp
index 5f41f2864f3c7..f05c62c487b6f 100644
--- a/src/joystick/gdk/SDL_gameinputjoystick.cpp
+++ b/src/joystick/gdk/SDL_gameinputjoystick.cpp
@@ -280,7 +280,7 @@ static bool GAMEINPUT_InternalAddOrFind(IGameInputDevice *pDevice)
 
     // Generate a device path
     for (idx = 0; idx < APP_LOCAL_DEVICE_ID_SIZE; ++idx) {
-        SDL_snprintf(tmp, SDL_arraysize(tmp), "%02hhX", info->deviceId.value[idx]);
+        SDL_snprintf(tmp, SDL_arraysize(tmp), "%02X", info->deviceId.value[idx]);
         SDL_strlcat(elem->path, tmp, SDL_arraysize(elem->path));
     }