No swap interval on composition.

src/win32_init.c

@@ -86,6 +86,13 @@ static GLboolean initLibraries(void)
             GetProcAddress(_glfw.win32.user32.instance, "SetProcessDPIAware");
     }
 
+    _glfw.win32.dwmapi.instance = LoadLibrary(L"dwmapi.dll");
+    if (_glfw.win32.dwmapi.instance)
+    {
+        _glfw.win32.dwmapi.DwmIsCompositionEnabled = (DWMISCOMPOSITIONENABLED_T)
+            GetProcAddress(_glfw.win32.dwmapi.instance, "DwmIsCompositionEnabled");
+    }
+
     return GL_TRUE;
 }
 
@@ -107,6 +114,21 @@ static void freeLibraries(void)
 //////                       GLFW internal API                      //////
 //////////////////////////////////////////////////////////////////////////
 
+// Returns whether desktop compositing is enabled
+//
+BOOL _glfwIsCompositionEnabled(void)
+{
+    BOOL enabled;
+
+    if (!_glfw_DwmIsCompositionEnabled)
+        return FALSE;
+
+    if (_glfw_DwmIsCompositionEnabled(&enabled) != S_OK)
+        return FALSE;
+
+    return enabled;
+}
+
 // Returns a wide string version of the specified UTF-8 string
 //
 WCHAR* _glfwCreateWideStringFromUTF8(const char* source)