diff --git a/configure.in b/configure.in
index 81b764200214..d930e30bf118 100644
--- a/configure.in
+++ b/configure.in
@@ -4394,7 +4394,6 @@ cairo-gtk2|cairo-gtk2-x11)
 
     TK_CFLAGS='$(MOZ_GTK2_CFLAGS)'
     TK_LIBS='$(MOZ_GTK2_LIBS)'
-    AC_DEFINE(MOZ_WIDGET_GTK2)
     MOZ_WIDGET_GTK=2
     AC_DEFINE_UNQUOTED(MOZ_WIDGET_GTK,$MOZ_WIDGET_GTK)
     MOZ_PDF_PRINTING=1
diff --git a/dom/plugins/base/nsNPAPIPlugin.cpp b/dom/plugins/base/nsNPAPIPlugin.cpp
index 05dfcd7b7b6a..501f82455215 100644
--- a/dom/plugins/base/nsNPAPIPlugin.cpp
+++ b/dom/plugins/base/nsNPAPIPlugin.cpp
@@ -1922,7 +1922,7 @@ _getvalue(NPP npp, NPNVariable variable, void *result)
         return NPERR_NO_ERROR;
       }
     }
-#ifdef MOZ_WIDGET_GTK2
+#if (MOZ_WIDGET_GTK == 2)
     // adobe nppdf calls XtGetApplicationNameAndClass(display,
     // &instance, &class) we have to init Xt toolkit before get
     // XtDisplay just call gtk_xtbin_new(w,0) once
@@ -1943,7 +1943,7 @@ _getvalue(NPP npp, NPNVariable variable, void *result)
     return NPERR_GENERIC_ERROR;
 #endif
 
-#if defined(XP_WIN) || defined(XP_OS2) || defined(MOZ_WIDGET_GTK2) \
+#if defined(XP_WIN) || defined(XP_OS2) || (MOZ_WIDGET_GTK == 2) \
  || defined(MOZ_WIDGET_QT)
   case NPNVnetscapeWindow: {
     if (!npp || !npp->ndata)
diff --git a/dom/plugins/base/nsNPAPIPluginInstance.cpp b/dom/plugins/base/nsNPAPIPluginInstance.cpp
index eb091006b052..97096b55ba44 100644
--- a/dom/plugins/base/nsNPAPIPluginInstance.cpp
+++ b/dom/plugins/base/nsNPAPIPluginInstance.cpp
@@ -556,7 +556,7 @@ nsresult nsNPAPIPluginInstance::SetWindow(NPWindow* window)
   if (!window || RUNNING != mRunning)
     return NS_OK;
 
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
   // bug 108347, flash plugin on linux doesn't like window->width <=
   // 0, but Java needs wants this call.
   if (!nsPluginHost::IsJavaMIMEType(mMIMEType) && window->type == NPWindowTypeWindow &&
diff --git a/dom/plugins/base/nsPluginInstanceOwner.cpp b/dom/plugins/base/nsPluginInstanceOwner.cpp
index 93ed1025d4d2..29b71f7e5e44 100644
--- a/dom/plugins/base/nsPluginInstanceOwner.cpp
+++ b/dom/plugins/base/nsPluginInstanceOwner.cpp
@@ -75,7 +75,7 @@ static NS_DEFINE_CID(kAppShellCID, NS_APPSHELL_CID);
 #include "nsPluginUtilsOSX.h"
 #endif
 
-#ifdef MOZ_WIDGET_GTK2
+#if (MOZ_WIDGET_GTK == 2)
 #include <gdk/gdk.h>
 #include <gdk/gdkx.h>
 #include <gtk/gtk.h>
diff --git a/dom/plugins/base/nsPluginStreamListenerPeer.cpp b/dom/plugins/base/nsPluginStreamListenerPeer.cpp
index b1759f47e43c..f06bce65104c 100644
--- a/dom/plugins/base/nsPluginStreamListenerPeer.cpp
+++ b/dom/plugins/base/nsPluginStreamListenerPeer.cpp
@@ -737,7 +737,7 @@ nsresult nsPluginStreamListenerPeer::ServeStreamAsFile(nsIRequest *request,
   if (owner) {
     NPWindow* window = nullptr;
     owner->GetWindow(window);
-#if defined(MOZ_WIDGET_GTK2) || defined(MOZ_WIDGET_QT)
+#if (MOZ_WIDGET_GTK == 2) || defined(MOZ_WIDGET_QT)
     // Should call GetPluginPort() here.
     // This part is copied from nsPluginInstanceOwner::GetPluginPort(). 
     nsCOMPtr<nsIWidget> widget;
diff --git a/dom/plugins/base/nsPluginsDirUnix.cpp b/dom/plugins/base/nsPluginsDirUnix.cpp
index ad1744a97cdd..3724366f515e 100644
--- a/dom/plugins/base/nsPluginsDirUnix.cpp
+++ b/dom/plugins/base/nsPluginsDirUnix.cpp
@@ -39,7 +39,7 @@
 #define DEFAULT_X11_PATH ""
 #endif
 
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
 
 #define PLUGIN_MAX_LEN_OF_TMP_ARR 512
 
@@ -265,7 +265,7 @@ nsresult nsPluginFile::LoadPlugin(PRLibrary **outLibrary)
 
     libSpec.value.pathname = path.get();
 
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
 
     // Normally, Mozilla isn't linked against libXt and libXext
     // since it's a Gtk/Gdk application.  On the other hand,
diff --git a/dom/plugins/ipc/PluginInstanceChild.cpp b/dom/plugins/ipc/PluginInstanceChild.cpp
index fb83400e55ea..83998fee28d0 100644
--- a/dom/plugins/ipc/PluginInstanceChild.cpp
+++ b/dom/plugins/ipc/PluginInstanceChild.cpp
@@ -1101,7 +1101,7 @@ PluginInstanceChild::AnswerNPP_SetWindow(const NPRemoteWindow& aWindow)
         CreateWindow(aWindow);
     }
 
-#ifdef MOZ_WIDGET_GTK2
+#if (MOZ_WIDGET_GTK == 2)
     if (mXEmbed && gtk_check_version(2,18,7) != NULL) { // older
         if (aWindow.type == NPWindowTypeWindow) {
             GdkWindow* socket_window = gdk_window_lookup(static_cast<GdkNativeWindow>(aWindow.window));
diff --git a/gfx/thebes/gfxFT2FontList.cpp b/gfx/thebes/gfxFT2FontList.cpp
index 258c8bf8fcd7..3453eee9d1a4 100644
--- a/gfx/thebes/gfxFT2FontList.cpp
+++ b/gfx/thebes/gfxFT2FontList.cpp
@@ -6,7 +6,7 @@
 #include "mozilla/MemoryReporting.h"
 #include "mozilla/Util.h"
 
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
 #include "gfxPlatformGtk.h"
 #define gfxToolkitPlatform gfxPlatformGtk
 #elif defined(MOZ_WIDGET_QT)
diff --git a/image/decoders/icon/nsIconModule.cpp b/image/decoders/icon/nsIconModule.cpp
index 4cf7c8f0d1d7..a3de26b6fa21 100644
--- a/image/decoders/icon/nsIconModule.cpp
+++ b/image/decoders/icon/nsIconModule.cpp
@@ -38,7 +38,7 @@ static const mozilla::Module::CategoryEntry kIconCategories[] = {
 static void
 IconDecoderModuleDtor()
 {
-#ifdef MOZ_WIDGET_GTK2
+#if (MOZ_WIDGET_GTK == 2)
   nsIconChannel::Shutdown();
 #endif
 }
diff --git a/layout/xul/base/src/nsMenuBarFrame.cpp b/layout/xul/base/src/nsMenuBarFrame.cpp
index dfad8ccbb4d1..762d32438282 100644
--- a/layout/xul/base/src/nsMenuBarFrame.cpp
+++ b/layout/xul/base/src/nsMenuBarFrame.cpp
@@ -149,7 +149,7 @@ nsMenuBarFrame::ToggleMenuActiveState()
       // Activate the menu bar
       SetActive(true);
 
-#ifdef MOZ_WIDGET_GTK2
+#if (MOZ_WIDGET_GTK == 2)
       firstFrame->OpenMenu(true);
 #else
       firstFrame->SelectMenu(true);
diff --git a/testing/tools/screenshot/gdk-screenshot.cpp b/testing/tools/screenshot/gdk-screenshot.cpp
index a8d713822fa4..0a356aa5daaa 100644
--- a/testing/tools/screenshot/gdk-screenshot.cpp
+++ b/testing/tools/screenshot/gdk-screenshot.cpp
@@ -61,7 +61,7 @@ int main(int argc, char** argv)
   gdk_init(&argc, &argv);
 
 // TODO GTK3
-#if defined(HAVE_LIBXSS) && defined(MOZ_WIDGET_GTK2)
+#if defined(HAVE_LIBXSS) && (MOZ_WIDGET_GTK == 2)
   int event_base, error_base;
   Bool have_xscreensaver =
     XScreenSaverQueryExtension(GDK_DISPLAY(), &event_base, &error_base);
@@ -129,7 +129,7 @@ int main(int argc, char** argv)
   GdkWindow* window = gdk_get_default_root_window();
   GdkPixbuf* screenshot = NULL;
 // TODO GTK3
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
   screenshot = gdk_pixbuf_get_from_drawable(NULL, window, NULL,
                                             0, 0, 0, 0,
                                             gdk_screen_width(),
diff --git a/toolkit/components/jsdownloads/src/DownloadPlatform.cpp b/toolkit/components/jsdownloads/src/DownloadPlatform.cpp
index a7a2c7eb89c2..8fad2458d9b4 100644
--- a/toolkit/components/jsdownloads/src/DownloadPlatform.cpp
+++ b/toolkit/components/jsdownloads/src/DownloadPlatform.cpp
@@ -25,7 +25,7 @@
 #include "AndroidBridge.h"
 #endif
 
-#ifdef MOZ_WIDGET_GTK2
+#if (MOZ_WIDGET_GTK == 2)
 #include <gtk/gtk.h>
 #endif
 
@@ -43,7 +43,7 @@ DownloadPlatform* DownloadPlatform::GetDownloadPlatform()
 
   NS_ADDREF(gDownloadPlatformService);
 
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
   g_type_init();
 #endif
 
@@ -67,10 +67,10 @@ static void gio_set_metadata_done(GObject *source_obj, GAsyncResult *res, gpoint
 nsresult DownloadPlatform::DownloadDone(nsIURI* aSource, nsIFile* aTarget,
                                         const nsACString& aContentType, bool aIsPrivate)
 {
-#if defined(XP_WIN) || defined(XP_MACOSX) || defined(MOZ_WIDGET_ANDROID) || defined(MOZ_WIDGET_GTK2)
+#if defined(XP_WIN) || defined(XP_MACOSX) || defined(MOZ_WIDGET_ANDROID) || (MOZ_WIDGET_GTK == 2)
   nsAutoString path;
   if (aTarget && NS_SUCCEEDED(aTarget->GetPath(path))) {
-#if defined(XP_WIN) || defined(MOZ_WIDGET_GTK2)
+#if defined(XP_WIN) || (MOZ_WIDGET_GTK == 2)
     // On Windows and Gtk, add the download to the system's "recent documents"
     // list, with a pref to disable.
     {
@@ -78,7 +78,7 @@ nsresult DownloadPlatform::DownloadDone(nsIURI* aSource, nsIFile* aTarget,
       if (addToRecentDocs && !aIsPrivate) {
 #ifdef XP_WIN
         ::SHAddToRecentDocs(SHARD_PATHW, path.get());
-#elif defined(MOZ_WIDGET_GTK2)
+#elif (MOZ_WIDGET_GTK == 2)
         GtkRecentManager* manager = gtk_recent_manager_get_default();
 
         gchar* uri = g_filename_to_uri(NS_ConvertUTF16toUTF8(path).get(),
diff --git a/toolkit/xre/nsX11ErrorHandler.cpp b/toolkit/xre/nsX11ErrorHandler.cpp
index d3a48ca468cf..97245e7b67c3 100644
--- a/toolkit/xre/nsX11ErrorHandler.cpp
+++ b/toolkit/xre/nsX11ErrorHandler.cpp
@@ -58,7 +58,7 @@ X11Error(Display *display, XErrorEvent *event) {
       }
       XCloseDisplay(tmpDisplay);
 
-#ifdef MOZ_WIDGET_GTK2
+#if (MOZ_WIDGET_GTK == 2)
       // GDK2 calls XCloseDevice the devices that it opened on startup, but
       // the XI protocol no longer ensures that the devices will still exist.
       // If they have been removed, then a BadDevice error results.  Ignore
diff --git a/widget/gtk2/gtkdrawing.h b/widget/gtk2/gtkdrawing.h
index 5d38574bd7ca..cce2f88e0762 100644
--- a/widget/gtk2/gtkdrawing.h
+++ b/widget/gtk2/gtkdrawing.h
@@ -209,7 +209,7 @@ gint moz_gtk_enable_style_props(style_prop_t styleGetProp);
  */
 gint moz_gtk_shutdown();
 
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
 /**
  * Retrieves the colormap to use for drawables passed to moz_gtk_widget_paint.
  */
@@ -217,7 +217,7 @@ GdkColormap* moz_gtk_widget_get_colormap();
 #endif
 
 /*** Widget drawing ***/
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
 /**
  * Paint a widget in the current theme.
  * widget:    a constant giving the widget to paint
diff --git a/widget/gtk2/mozcontainer.c b/widget/gtk2/mozcontainer.c
index 262ea6749c33..ded61f678b55 100644
--- a/widget/gtk2/mozcontainer.c
+++ b/widget/gtk2/mozcontainer.c
@@ -236,14 +236,14 @@ moz_container_realize (GtkWidget *widget)
         attributes.visual = gtk_widget_get_visual (widget);
         attributes.window_type = GDK_WINDOW_CHILD;
 
-#if defined(MOZ_WIDGET_GTK2)    
+#if (MOZ_WIDGET_GTK == 2)
         attributes.colormap = gtk_widget_get_colormap (widget);
         attributes_mask |= GDK_WA_COLORMAP;
 #endif
 
         window = gdk_window_new (parent, &attributes, attributes_mask);
         gdk_window_set_user_data (window, widget);
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
         /* TODO GTK3? */
         /* set the back pixmap to None so that you don't end up with the gtk
            default which is BlackPixel */
@@ -256,7 +256,7 @@ moz_container_realize (GtkWidget *widget)
 
     gtk_widget_set_window (widget, window);
 
-#if defined(MOZ_WIDGET_GTK2)    
+#if (MOZ_WIDGET_GTK == 2)
     widget->style = gtk_style_attach (widget->style, widget->window);
 #endif
 }
diff --git a/widget/gtk2/nsNativeThemeGTK.cpp b/widget/gtk2/nsNativeThemeGTK.cpp
index a22741a97e16..5c4833063342 100644
--- a/widget/gtk2/nsNativeThemeGTK.cpp
+++ b/widget/gtk2/nsNativeThemeGTK.cpp
@@ -630,7 +630,7 @@ nsNativeThemeGTK::GetGtkWidgetAndState(uint8_t aWidgetType, nsIFrame* aFrame,
   return true;
 }
 
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
 class ThemeRenderer : public gfxGdkNativeRenderer {
 public:
   ThemeRenderer(GtkWidgetState aState, GtkThemeWidgetType aGTKWidgetType,
@@ -822,7 +822,7 @@ nsNativeThemeGTK::DrawWidgetBackground(nsRenderingContext* aContext,
     gdk_error_trap_push ();
   }
 
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
   // The gdk_clip is just advisory here, meaning "you don't
   // need to draw outside this rect if you don't feel like it!"
   GdkRectangle gdk_clip = {0, 0, drawingRect.width, drawingRect.height};
diff --git a/widget/gtk2/nsWindow.cpp b/widget/gtk2/nsWindow.cpp
index 1e24d7593473..4f844373d601 100644
--- a/widget/gtk2/nsWindow.cpp
+++ b/widget/gtk2/nsWindow.cpp
@@ -44,7 +44,7 @@
 #endif
 #endif /* MOZ_X11 */
 #include <gdk/gdkkeysyms.h>
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
 #include <gtk/gtkprivate.h>
 #endif
 
@@ -156,7 +156,7 @@ static int    is_parent_grab_leave(GdkEventCrossing *aEvent);
 static void GetBrandName(nsXPIDLString& brandName);
 
 /* callbacks from widgets */
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
 static gboolean expose_event_cb           (GtkWidget *widget,
                                            GdkEventExpose *event);
 #else
@@ -302,7 +302,7 @@ protected:
 static inline int32_t
 GetBitmapStride(int32_t width)
 {
-#if defined(MOZ_X11) || defined(MOZ_WIDGET_GTK2)
+#if defined(MOZ_X11) || (MOZ_WIDGET_GTK == 2)
   return (width+7)/8;
 #else
   return cairo_format_stride_for_width(CAIRO_FORMAT_A1, width);
@@ -651,7 +651,7 @@ nsWindow::Destroy(void)
         gFocusWindow = nullptr;
     }
 
-#if defined(MOZ_WIDGET_GTK2) && defined(MOZ_X11)
+#if (MOZ_WIDGET_GTK == 2) && defined(MOZ_X11)
     // make sure that we remove ourself as the plugin focus window
     if (gPluginFocusWindow == this) {
         gPluginFocusWindow->LoseNonXEmbedPluginFocus();
@@ -1907,7 +1907,7 @@ gdk_window_flash(GdkWindow *    aGdkWindow,
   GdkGC *      gc = 0;
   GdkColor     white;
 
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
   gdk_window_get_geometry(aGdkWindow,NULL,NULL,&width,&height,NULL);
 #else
   gdk_window_get_geometry(aGdkWindow,NULL,NULL,&width,&height);
@@ -1955,7 +1955,7 @@ gdk_window_flash(GdkWindow *    aGdkWindow,
 #endif // DEBUG
 #endif
 
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
 gboolean
 nsWindow::OnExposeEvent(GdkEventExpose *aEvent)
 #else
@@ -2000,7 +2000,7 @@ nsWindow::OnExposeEvent(cairo_t *cr)
             return FALSE;
     }
 
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
     GdkRectangle *rects;
     gint nrects;
     gdk_region_get_rectangles(aEvent->region, &rects, &nrects);
@@ -2020,7 +2020,7 @@ nsWindow::OnExposeEvent(cairo_t *cr)
 #endif
 
 // GTK3 TODO?
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
     if (nrects > MAX_RECTS_IN_REGION) {
         // Just use the bounding box
         rects[0] = aEvent->area;
@@ -2034,7 +2034,7 @@ nsWindow::OnExposeEvent(cairo_t *cr)
 
     nsIntRegion region;
   
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
     GdkRectangle *r = rects;
     GdkRectangle *r_end = rects + nrects;
 #else
@@ -2087,7 +2087,7 @@ nsWindow::OnExposeEvent(cairo_t *cr)
     }
 
     if (region.IsEmpty()) {
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
         g_free(rects);
 #else
         cairo_rectangle_list_destroy(rects);
@@ -2112,7 +2112,7 @@ nsWindow::OnExposeEvent(cairo_t *cr)
         return TRUE;
     }
 
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
     nsRefPtr<gfxContext> ctx = new gfxContext(GetThebesSurface());
 #else
     nsRefPtr<gfxContext> ctx = new gfxContext(GetThebesSurface(cr));
@@ -2207,7 +2207,7 @@ nsWindow::OnExposeEvent(cairo_t *cr)
     }
 #  ifdef MOZ_HAVE_SHMIMAGE
     if (nsShmImage::UseShm() && MOZ_LIKELY(!mIsDestroyed)) {
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
         mShmImage->Put(mGdkWindow, rects, r_end);
 #else
         mShmImage->Put(mGdkWindow, rects);
@@ -2216,7 +2216,7 @@ nsWindow::OnExposeEvent(cairo_t *cr)
 #  endif  // MOZ_HAVE_SHMIMAGE
 #endif // MOZ_X11
 
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
     g_free(rects);
 #else
     cairo_rectangle_list_destroy(rects);
@@ -2225,7 +2225,7 @@ nsWindow::OnExposeEvent(cairo_t *cr)
     listener->DidPaintWindow();
 
     // Synchronously flush any new dirty areas
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
     GdkRegion* dirtyArea = gdk_window_get_update_area(mGdkWindow);
 #else
     cairo_region_t* dirtyArea = gdk_window_get_update_area(mGdkWindow);
@@ -2233,7 +2233,7 @@ nsWindow::OnExposeEvent(cairo_t *cr)
 
     if (dirtyArea) {
         gdk_window_invalidate_region(mGdkWindow, dirtyArea, false);
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
         gdk_region_destroy(dirtyArea);
 #else
         cairo_region_destroy(dirtyArea);
@@ -2466,7 +2466,7 @@ nsWindow::OnMotionNotifyEvent(GdkEventMotion *aEvent)
         synthEvent = true;
         XNextEvent (GDK_WINDOW_XDISPLAY(aEvent->window), &xevent);
     }
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
     // if plugins still keeps the focus, get it back
     if (gPluginFocusWindow && gPluginFocusWindow != this) {
         nsRefPtr<nsWindow> kungFuDeathGrip = gPluginFocusWindow;
@@ -2814,7 +2814,7 @@ nsWindow::OnContainerFocusOutEvent(GdkEventFocus *aEvent)
         }
     }
 
-#if defined(MOZ_WIDGET_GTK2) && defined(MOZ_X11)
+#if (MOZ_WIDGET_GTK == 2) && defined(MOZ_X11)
     // plugin lose focus
     if (gPluginFocusWindow) {
         nsRefPtr<nsWindow> kungFuDeathGrip = gPluginFocusWindow;
@@ -3279,7 +3279,7 @@ CreateGdkWindow(GdkWindow *parent, GtkWidget *widget)
     attributes.visual = gtk_widget_get_visual(widget);
     attributes.window_type = GDK_WINDOW_CHILD;
 
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
     attributes_mask |= GDK_WA_COLORMAP;
     attributes.colormap = gtk_widget_get_colormap(widget);
 #endif
@@ -3288,7 +3288,7 @@ CreateGdkWindow(GdkWindow *parent, GtkWidget *widget)
     gdk_window_set_user_data(window, widget);
 
 // GTK3 TODO?
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
     /* set the default pixmap to None so that you don't end up with the
        gtk default which is BlackPixel. */
     gdk_window_set_back_pixmap(window, NULL, FALSE);
@@ -3420,7 +3420,7 @@ nsWindow::Create(nsIWidget        *aParent,
                 // are on a compositing window manager.
                 GdkScreen *screen = gtk_widget_get_screen(mShell);
                 if (gdk_screen_is_composited(screen)) {
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
                     GdkColormap *colormap =
                         gdk_screen_get_rgba_colormap(screen);
                     gtk_widget_set_colormap(mShell, colormap);
@@ -3599,7 +3599,7 @@ nsWindow::Create(nsIWidget        *aParent,
         hierarchy_changed_cb(GTK_WIDGET(mContainer), NULL);
         // Expose, focus, key, and drag events are sent even to GTK_NO_WINDOW
         // widgets.
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
         g_signal_connect(mContainer, "expose_event",
                          G_CALLBACK(expose_event_cb), NULL);
 #else
@@ -3656,7 +3656,7 @@ nsWindow::Create(nsIWidget        *aParent,
     }
 
     if (eventWidget) {
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
         // Don't let GTK mess with the shapes of our GdkWindows
         GTK_PRIVATE_SET_FLAG(eventWidget, GTK_HAS_SHAPE_MASK);
 #endif
@@ -4097,7 +4097,7 @@ nsWindow::SetWindowClipRegion(const nsTArray<nsIntRect>& aRects,
     if (!mGdkWindow)
         return;
 
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
     GdkRegion *region = gdk_region_new(); // aborts on OOM
     for (uint32_t i = 0; i < newRects->Length(); ++i) {
         const nsIntRect& r = newRects->ElementAt(i);
@@ -4227,7 +4227,7 @@ nsWindow::ApplyTransparencyBitmap()
                       maskPixmap, ShapeSet);
     XFreePixmap(xDisplay, maskPixmap);
 #else
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
     gtk_widget_reset_shapes(mShell);
     GdkBitmap* maskBitmap = gdk_bitmap_create_from_data(gtk_widget_get_window(mShell),
             mTransparencyBitmap,
@@ -4496,7 +4496,7 @@ nsWindow::SetNonXEmbedPluginFocus()
     LOGFOCUS(("\t curFocusWindow=%p\n", curFocusWindow));
 
     GdkWindow* toplevel = gdk_window_get_toplevel(mGdkWindow);
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
     GdkWindow *gdkfocuswin = gdk_window_lookup(curFocusWindow);
 #else
     GdkWindow *gdkfocuswin = gdk_x11_window_lookup_for_display(gdkDisplay,
@@ -4779,7 +4779,7 @@ is_mouse_in_window (GdkWindow* aWindow, gdouble aMouseX, gdouble aMouseY)
         window = gdk_window_get_parent(window);
     }
 
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
     gdk_drawable_get_size(aWindow, &w, &h);
 #else
     w = gdk_window_get_width(aWindow);
@@ -4983,7 +4983,7 @@ get_gtk_cursor(nsCursor aCursor)
 
 // gtk callbacks
 
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
 static gboolean
 expose_event_cb(GtkWidget *widget, GdkEventExpose *event)
 {
@@ -5290,7 +5290,7 @@ plugin_window_filter_func(GdkXEvent *gdk_xevent, GdkEvent *event, gpointer data)
                     break;
                 xeventWindow = xevent->xreparent.window;
             }
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
             plugin_window = gdk_window_lookup(xeventWindow);
 #else
             plugin_window = gdk_x11_window_lookup_for_display(
@@ -5301,7 +5301,7 @@ plugin_window_filter_func(GdkXEvent *gdk_xevent, GdkEvent *event, gpointer data)
                     get_gtk_widget_for_gdk_window(plugin_window);
 
 // TODO GTK3
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
                 if (GTK_IS_XTBIN(widget)) {
                     nswindow->SetPluginType(nsWindow::PluginType_NONXEMBED);
                     break;
@@ -5668,7 +5668,7 @@ get_inner_gdk_window (GdkWindow *aWindow,
          child = g_list_previous(child)) {
         GdkWindow *childWindow = (GdkWindow *) child->data;
         if (get_window_for_gdk_window(childWindow)) {
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
             gdk_window_get_geometry(childWindow, &cx, &cy, &cw, &ch, NULL);
 #else
             gdk_window_get_geometry(childWindow, &cx, &cy, &cw, &ch);
@@ -5868,7 +5868,7 @@ nsWindow::GetToggledKeyState(uint32_t aKeyCode, bool* aLEDState)
     return NS_OK;
 }
 
-#if defined(MOZ_X11) && defined(MOZ_WIDGET_GTK2)
+#if defined(MOZ_X11) && (MOZ_WIDGET_GTK == 2)
 /* static */ already_AddRefed<gfxASurface>
 nsWindow::GetSurfaceForGdkDrawable(GdkDrawable* aDrawable,
                                    const nsIntSize& aSize)
@@ -5910,7 +5910,7 @@ nsWindow::GetSurfaceForGdkDrawable(GdkDrawable* aDrawable,
 }
 #endif
 
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
 TemporaryRef<DrawTarget>
 nsWindow::StartRemoteDrawing()
 {
@@ -5930,7 +5930,7 @@ nsWindow::StartRemoteDrawing()
 
 // return the gfxASurface for rendering to this widget
 gfxASurface*
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
 nsWindow::GetThebesSurface()
 #else
 nsWindow::GetThebesSurface(cairo_t *cr)
@@ -5939,7 +5939,7 @@ nsWindow::GetThebesSurface(cairo_t *cr)
     if (!mGdkWindow)
         return nullptr;
 
-#if !defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK != 2)
     cairo_surface_t *surf = cairo_get_target(cr);
     if (cairo_surface_status(surf) != CAIRO_STATUS_SUCCESS) {
       NS_NOTREACHED("Missing cairo target?");
@@ -5950,7 +5950,7 @@ nsWindow::GetThebesSurface(cairo_t *cr)
 #ifdef MOZ_X11
     gint width, height;
 
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
     gdk_drawable_get_size(GDK_DRAWABLE(mGdkWindow), &width, &height);
 #else
     width = gdk_window_get_width(mGdkWindow);
@@ -5980,7 +5980,7 @@ nsWindow::GetThebesSurface(cairo_t *cr)
     if (!usingShm)
 #  endif  // MOZ_HAVE_SHMIMAGE
 
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
     mThebesSurface = new gfxXlibSurface
         (GDK_WINDOW_XDISPLAY(mGdkWindow),
          gdk_x11_window_get_xid(mGdkWindow),
diff --git a/widget/gtk2/nsWindow.h b/widget/gtk2/nsWindow.h
index 076a8e16d087..0651b9876965 100644
--- a/widget/gtk2/nsWindow.h
+++ b/widget/gtk2/nsWindow.h
@@ -164,7 +164,7 @@ public:
     gint               ConvertBorderStyles(nsBorderStyle aStyle);
 
     // event callbacks
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
     gboolean           OnExposeEvent(GdkEventExpose *aEvent);
 #else
     gboolean           OnExposeEvent(cairo_t *cr);
@@ -196,7 +196,7 @@ public:
                                                guint            aTime,
                                                gpointer         aData);
 
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
   mozilla::TemporaryRef<mozilla::gfx::DrawTarget> StartRemoteDrawing() MOZ_OVERRIDE;
 #endif
 
@@ -277,7 +277,7 @@ public:
    nsresult            UpdateTranslucentWindowAlphaInternal(const nsIntRect& aRect,
                                                             uint8_t* aAlphas, int32_t aStride);
 
-#if defined(MOZ_WIDGET_GTK2)
+#if (MOZ_WIDGET_GTK == 2)
     gfxASurface       *GetThebesSurface();
 
     static already_AddRefed<gfxASurface> GetSurfaceForGdkDrawable(GdkDrawable* aDrawable,