2 files changed, 67 insertions, 0 deletions
diff --git a/widget/gtk/mozgtk/moz.build b/widget/gtk/mozgtk/moz.build
new file mode 100644
index 0000000000..d5e78d0032
--- /dev/null
+++ b/widget/gtk/mozgtk/moz.build
@@ -0,0 +1,37 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+SharedLibrary("mozgtk")
+
+SOURCES += [
+    "mozgtk.c",
+]
+
+CFLAGS += CONFIG["MOZ_X11_CFLAGS"]
+CFLAGS += CONFIG["MOZ_GTK3_CFLAGS"]
+
+# If LDFLAGS contains -Wl,--as-needed or if it's the default for the toolchain,
+# we need to add -Wl,--no-as-needed before the gtk libraries, otherwise the
+# linker will drop those dependencies because no symbols are used from them.
+# But those dependencies need to be kept for things to work properly.
+# Ideally, we'd only add -Wl,--no-as-needed if necessary, but it's just simpler
+# to add it unconditionally. This library is also simple enough that forcing
+# -Wl,--as-needed after the gtk libraries is not going to make a significant
+# difference.
+if CONFIG["GCC_USE_GNU_LD"]:
+    no_as_needed = ["-Wl,--no-as-needed"]
+    as_needed = ["-Wl,--as-needed"]
+else:
+    no_as_needed = []
+    as_needed = []
+
+OS_LIBS += [f for f in CONFIG["MOZ_GTK3_LIBS"] if f.startswith("-L")]
+OS_LIBS += no_as_needed
+OS_LIBS += [
+    "gtk-3",
+    "gdk-3",
+]
+OS_LIBS += as_needed
diff --git a/widget/gtk/mozgtk/mozgtk.c b/widget/gtk/mozgtk/mozgtk.c
new file mode 100644
index 0000000000..d95746fc0b
--- /dev/null
+++ b/widget/gtk/mozgtk/mozgtk.c
@@ -0,0 +1,30 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/Types.h"
+
+#include <gdk/gdk.h>
+
+// Dummy call to gtk3 library to prevent the linker from removing
+// the gtk3 dependency with --as-needed.
+// see toolkit/library/moz.build for details.
+MOZ_EXPORT void mozgtk_linker_holder() { gdk_display_get_default(); }
+
+#ifdef MOZ_X11
+#  include <X11/Xlib.h>
+// Bug 1271100
+// We need to trick system Cairo into not using the XShm extension due to
+// a race condition in it that results in frequent BadAccess errors. Cairo
+// relies upon XShmQueryExtension to initially detect if XShm is available.
+// So we define our own stub that always indicates XShm not being present.
+// mozgtk loads before libXext/libcairo and so this stub will take priority.
+// Our tree usage goes through xcb and remains unaffected by this.
+//
+// This is also used to force libxul to depend on the mozgtk library. If we
+// ever can remove this workaround for system Cairo, we'll need something
+// to replace it for that purpose.
+MOZ_EXPORT Bool XShmQueryExtension(Display* aDisplay) { return False; }
+#endif