diff --git a/CMakeLists.txt b/CMakeLists.txt
index 1ff15f0d..efb559c9 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -288,18 +288,18 @@ if (_GLFW_X11)
     endif()
 
     # Check for Xf86VidMode (fallback gamma control)
-    if (NOT X11_xf86vmode_FOUND)
-        message(FATAL_ERROR "The Xf86VidMode library and headers were not found")
-    endif()
+    if (X11_xf86vmode_FOUND)
+        list(APPEND glfw_INCLUDE_DIRS "${X11_xf86vmode_INCLUDE_PATH}")
+        list(APPEND glfw_PKG_DEPS "xxf86vm")
 
-    list(APPEND glfw_INCLUDE_DIRS "${X11_xf86vmode_INCLUDE_PATH}")
-    list(APPEND glfw_PKG_DEPS "xxf86vm")
+        if (X11_Xxf86vm_LIB)
+            list(APPEND glfw_LIBRARIES "${X11_Xxf86vm_LIB}")
+        else()
+            # Backwards compatibility (see CMake bug 0006976)
+            list(APPEND glfw_LIBRARIES Xxf86vm)
+        endif()
 
-    if (X11_Xxf86vm_LIB)
-        list(APPEND glfw_LIBRARIES "${X11_Xxf86vm_LIB}")
-    else()
-        # Backwards compatibility (see CMake bug 0006976)
-        list(APPEND glfw_LIBRARIES Xxf86vm)
+        set(_GLFW_HAS_XF86VM TRUE)
     endif()
 
     # Check for Xkb (X keyboard extension)
diff --git a/README.md b/README.md
index 9d26bdf6..00e4c5c7 100644
--- a/README.md
+++ b/README.md
@@ -65,6 +65,7 @@ GLFW bundles a number of dependencies in the `deps/` directory.
  - [Cocoa] Bugfix: `glfwSetWindowSize` did not change the video mode for full
                    screen windows
  - [X11] Made XInput2 optional at compile-time
+ - [X11] Made Xxf86vm optional at compile-time
 
 
 ## Contact
diff --git a/src/glfw_config.h.in b/src/glfw_config.h.in
index 842fa432..296c96de 100644
--- a/src/glfw_config.h.in
+++ b/src/glfw_config.h.in
@@ -64,6 +64,8 @@
 
 // Define this to 1 if the XInput X11 extension is available
 #cmakedefine _GLFW_HAS_XINPUT
+// Define this to 1 if the Xxf86vm X11 extension is available
+#cmakedefine _GLFW_HAS_XF86VM
 // Define this to 1 if glXGetProcAddress is available
 #cmakedefine _GLFW_HAS_GLXGETPROCADDRESS
 // Define this to 1 if glXGetProcAddressARB is available
diff --git a/src/x11_init.c b/src/x11_init.c
index aa9c1c2c..dc33bcee 100644
--- a/src/x11_init.c
+++ b/src/x11_init.c
@@ -479,11 +479,13 @@ static GLboolean initExtensions(void)
                                            "_MOTIF_WM_HINTS",
                                            False);
 
+#if defined(_GLFW_HAS_XF86VM)
     // Check for XF86VidMode extension
     _glfw.x11.vidmode.available =
         XF86VidModeQueryExtension(_glfw.x11.display,
                                   &_glfw.x11.vidmode.eventBase,
                                   &_glfw.x11.vidmode.errorBase);
+#endif /*_GLFW_HAS_XF86VM*/
 
     // Check for RandR extension
     _glfw.x11.randr.available =
diff --git a/src/x11_monitor.c b/src/x11_monitor.c
index 6265070f..cdb1c92a 100644
--- a/src/x11_monitor.c
+++ b/src/x11_monitor.c
@@ -432,6 +432,7 @@ void _glfwPlatformGetGammaRamp(_GLFWmonitor* monitor, GLFWgammaramp* ramp)
 
         XRRFreeGamma(gamma);
     }
+#if defined(_GLFW_HAS_XF86VM)
     else if (_glfw.x11.vidmode.available)
     {
         int size;
@@ -443,6 +444,7 @@ void _glfwPlatformGetGammaRamp(_GLFWmonitor* monitor, GLFWgammaramp* ramp)
                                 _glfw.x11.screen,
                                 ramp->size, ramp->red, ramp->green, ramp->blue);
     }
+#endif /*_GLFW_HAS_XF86VM*/
 }
 
 void _glfwPlatformSetGammaRamp(_GLFWmonitor* monitor, const GLFWgammaramp* ramp)
@@ -458,6 +460,7 @@ void _glfwPlatformSetGammaRamp(_GLFWmonitor* monitor, const GLFWgammaramp* ramp)
         XRRSetCrtcGamma(_glfw.x11.display, monitor->x11.crtc, gamma);
         XRRFreeGamma(gamma);
     }
+#if defined(_GLFW_HAS_XF86VM)
     else if (_glfw.x11.vidmode.available)
     {
         XF86VidModeSetGammaRamp(_glfw.x11.display,
@@ -467,6 +470,7 @@ void _glfwPlatformSetGammaRamp(_GLFWmonitor* monitor, const GLFWgammaramp* ramp)
                                 (unsigned short*) ramp->green,
                                 (unsigned short*) ramp->blue);
     }
+#endif /*_GLFW_HAS_XF86VM*/
 }
 
 
diff --git a/src/x11_platform.h b/src/x11_platform.h
index d1572ba8..0c6450b3 100644
--- a/src/x11_platform.h
+++ b/src/x11_platform.h
@@ -37,9 +37,6 @@
 #include <X11/Xatom.h>
 #include <X11/Xcursor/Xcursor.h>
 
-// The Xf86VidMode extension provides fallback gamma control
-#include <X11/extensions/xf86vmode.h>
-
 // The XRandR extension provides mode setting and gamma control
 #include <X11/extensions/Xrandr.h>
 
@@ -54,6 +51,11 @@
  #include <X11/extensions/XInput2.h>
 #endif
 
+#if defined(_GLFW_HAS_XF86VM)
+ // The Xf86VidMode extension provides fallback gamma control
+ #include <X11/extensions/xf86vmode.h>
+#endif
+
 #include "posix_tls.h"
 
 #if defined(_GLFW_GLX)
@@ -164,12 +166,6 @@ typedef struct _GLFWlibraryX11
     Atom            ATOM_PAIR;
     Atom            GLFW_SELECTION;
 
-    struct {
-        GLboolean   available;
-        int         eventBase;
-        int         errorBase;
-    } vidmode;
-
     struct {
         GLboolean   available;
         int         eventBase;
@@ -219,6 +215,14 @@ typedef struct _GLFWlibraryX11
     } xi;
 #endif /*_GLFW_HAS_XINPUT*/
 
+#if defined(_GLFW_HAS_XF86VM)
+    struct {
+        GLboolean   available;
+        int         eventBase;
+        int         errorBase;
+    } vidmode;
+#endif /*_GLFW_HAS_XF86VM*/
+
 } _GLFWlibraryX11;