Backends: avoid missing -Wmissing-declaration warning.  (#8087, #7997)
diff --git a/backends/imgui_impl_allegro5.cpp b/backends/imgui_impl_allegro5.cpp
index 9c25716..d5d6570 100644
--- a/backends/imgui_impl_allegro5.cpp
+++ b/backends/imgui_impl_allegro5.cpp
@@ -311,6 +311,7 @@
 #endif
 
 // Not static to allow third-party code to use that if they want to (but undocumented)
+ImGuiKey ImGui_ImplAllegro5_KeyCodeToImGuiKey(int key_code);
 ImGuiKey ImGui_ImplAllegro5_KeyCodeToImGuiKey(int key_code)
 {
     switch (key_code)
diff --git a/backends/imgui_impl_glfw.cpp b/backends/imgui_impl_glfw.cpp
index c725e9c..774fb0d 100644
--- a/backends/imgui_impl_glfw.cpp
+++ b/backends/imgui_impl_glfw.cpp
@@ -187,6 +187,7 @@
 // Functions
 
 // Not static to allow third-party code to use that if they want to (but undocumented)
+ImGuiKey ImGui_ImplGlfw_KeyToImGuiKey(int keycode, int scancode);
 ImGuiKey ImGui_ImplGlfw_KeyToImGuiKey(int keycode, int scancode)
 {
     IM_UNUSED(scancode);
diff --git a/backends/imgui_impl_osx.mm b/backends/imgui_impl_osx.mm
index 3115bf1..de9b574 100644
--- a/backends/imgui_impl_osx.mm
+++ b/backends/imgui_impl_osx.mm
@@ -261,6 +261,7 @@
 // Functions
 
 // Not static to allow third-party code to use that if they want to (but undocumented)
+ImGuiKey ImGui_ImplOSX_KeyCodeToImGuiKey(int key_code);
 ImGuiKey ImGui_ImplOSX_KeyCodeToImGuiKey(int key_code)
 {
     switch (key_code)
diff --git a/backends/imgui_impl_sdl2.cpp b/backends/imgui_impl_sdl2.cpp
index 7a8af3b..529ca79 100644
--- a/backends/imgui_impl_sdl2.cpp
+++ b/backends/imgui_impl_sdl2.cpp
@@ -182,6 +182,7 @@
 }
 
 // Not static to allow third-party code to use that if they want to (but undocumented)
+ImGuiKey ImGui_ImplSDL2_KeyEventToImGuiKey(SDL_Keycode keycode, SDL_Scancode scancode);
 ImGuiKey ImGui_ImplSDL2_KeyEventToImGuiKey(SDL_Keycode keycode, SDL_Scancode scancode)
 {
     IM_UNUSED(scancode);
diff --git a/backends/imgui_impl_sdl3.cpp b/backends/imgui_impl_sdl3.cpp
index ca960ca..de8b531 100644
--- a/backends/imgui_impl_sdl3.cpp
+++ b/backends/imgui_impl_sdl3.cpp
@@ -161,6 +161,7 @@
 }
 
 // Not static to allow third-party code to use that if they want to (but undocumented)
+ImGuiKey ImGui_ImplSDL3_KeyEventToImGuiKey(SDL_Keycode keycode, SDL_Scancode scancode);
 ImGuiKey ImGui_ImplSDL3_KeyEventToImGuiKey(SDL_Keycode keycode, SDL_Scancode scancode)
 {
     // Keypad doesn't have individual key values in SDL3
diff --git a/backends/imgui_impl_win32.cpp b/backends/imgui_impl_win32.cpp
index bbfa1a5..477d54a 100644
--- a/backends/imgui_impl_win32.cpp
+++ b/backends/imgui_impl_win32.cpp
@@ -421,6 +421,7 @@
 
 // Map VK_xxx to ImGuiKey_xxx.
 // Not static to allow third-party code to use that if they want to (but undocumented)
+ImGuiKey ImGui_ImplWin32_KeyEventToImGuiKey(WPARAM wParam, LPARAM lParam);
 ImGuiKey ImGui_ImplWin32_KeyEventToImGuiKey(WPARAM wParam, LPARAM lParam)
 {
     // There is no distinct VK_xxx for keypad enter, instead it is VK_RETURN + KF_EXTENDED.