Backends: GLFW: try to set IMGUI_IMPL_GLFW_DISABLE_X11 / IMGUI_IMPL_GLFW_DISABLE_WAYLAND automatically if headers are not available. (#9225)

Amend/fix 10d0162378 for system without X11/Wayland headers. (#8921, #8920, #8969)

backends/imgui_impl_glfw.cpp

diff --git a/backends/imgui_impl_glfw.cpp b/backends/imgui_impl_glfw.cpp
index f166b45..da54589 100644
--- a/backends/imgui_impl_glfw.cpp
+++ b/backends/imgui_impl_glfw.cpp
@@ -29,6 +29,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2026-02-10: Try to set IMGUI_IMPL_GLFW_DISABLE_X11 / IMGUI_IMPL_GLFW_DISABLE_WAYLAND automatically if corresponding headers are not accessible. (#9225)
 //  2025-12-12: Added IMGUI_IMPL_GLFW_DISABLE_X11 / IMGUI_IMPL_GLFW_DISABLE_WAYLAND to forcefully disable either.
 //  2025-12-10: Avoid repeated glfwSetCursor()/glfwSetInputMode() calls when unnecessary. Lowers overhead for very high framerates (e.g. 10k+ FPS).
 //  2025-11-06: Lower minimum requirement to GLFW 3.0. Though a recent version e.g GLFW 3.4 is highly recommended.
@@ -109,6 +110,15 @@
 #pragma clang diagnostic ignored "-Wglobal-constructors"    // warning: declaration requires a global destructor         // similar to above, not sure what the exact difference is.
 #endif
 
+#if defined(__has_include)
+#if !__has_include(<X11/Xlib.h>) || !__has_include(<X11/extensions/Xrandr.h>)
+#define IMGUI_IMPL_GLFW_DISABLE_X11
+#endif
+#if !__has_include(<wayland-client.h>)
+#define IMGUI_IMPL_GLFW_DISABLE_WAYLAND
+#endif
+#endif
+
 // GLFW
 #if !defined(IMGUI_IMPL_GLFW_DISABLE_X11) && (defined(__linux__) || defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__NetBSD__) || defined(__DragonFly__))
 #define GLFW_HAS_X11        1

docs/CHANGELOG.txt

diff --git a/docs/CHANGELOG.txt b/docs/CHANGELOG.txt
index 00349b9..69da227 100644
--- a/docs/CHANGELOG.txt
+++ b/docs/CHANGELOG.txt
@@ -219,6 +219,7 @@
     Lowers overhead for very high framerates (e.g. 10k+ FPS). [@maxliani]
   - GLFW: Added IMGUI_IMPL_GLFW_DISABLE_X11 / IMGUI_IMPL_GLFW_DISABLE_WAYLAND to
     forcefully disable either. (#9109, #9116)
+    Try to set them automatically if headers are not accessible. (#9225)
   - OpenGL3: Fixed embedded loader multiple init/shutdown cycles broken on some
     platforms. (#8792, #9112)
   - SDL2, SDL3: changed `GetClipboardText()` handler to return NULL on error aka