Backends: GLFW: Only enable Vulkan support if not building with Emscripten (#6468)

backends/imgui_impl_glfw.cpp

@@ -102,7 +102,11 @@
 #define GLFW_HAS_WINDOW_HOVERED         (GLFW_VERSION_COMBINED >= 3300) // 3.3+ GLFW_HOVERED
 #define GLFW_HAS_WINDOW_ALPHA           (GLFW_VERSION_COMBINED >= 3300) // 3.3+ glfwSetWindowOpacity
 #define GLFW_HAS_PER_MONITOR_DPI        (GLFW_VERSION_COMBINED >= 3300) // 3.3+ glfwGetMonitorContentScale
+#ifdef __EMSCRIPTEN__                   // no Vulkan support in Emscripten's GLFW
+#define GLFW_HAS_VULKAN                 (0)
+#else
 #define GLFW_HAS_VULKAN                 (GLFW_VERSION_COMBINED >= 3200) // 3.2+ glfwCreateWindowSurface
+#endif
 #define GLFW_HAS_FOCUS_WINDOW           (GLFW_VERSION_COMBINED >= 3200) // 3.2+ glfwFocusWindow
 #define GLFW_HAS_FOCUS_ON_SHOW          (GLFW_VERSION_COMBINED >= 3300) // 3.3+ GLFW_FOCUS_ON_SHOW
 #define GLFW_HAS_MONITOR_WORK_AREA      (GLFW_VERSION_COMBINED >= 3300) // 3.3+ glfwGetMonitorWorkarea