import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

toolkit/library/StaticXULComponentsEnd/StaticXULComponentsEnd.cpp

@@ -0,0 +1,13 @@
+#include "mozilla/Module.h"
+
+/* Ensure end_kPStaticModules is at the end of the .kPStaticModules section
+ * on Windows. Somehow, placing the object last is not enough with PGO/LTCG. */
+#ifdef _MSC_VER
+/* Sections on Windows are in two parts, separated with $. When linking,
+ * sections with the same first part are all grouped, and ordered
+ * alphabetically with the second part as sort key. */
+#  pragma section(".kPStaticModules$Z", read)
+#  undef NSMODULE_SECTION
+#  define NSMODULE_SECTION __declspec(allocate(".kPStaticModules$Z"), dllexport)
+#endif
+NSMODULE_DEFN(end_kPStaticModules) = nullptr;

toolkit/library/StaticXULComponentsEnd/moz.build

@@ -0,0 +1,15 @@
+# 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/.
+
+SOURCES += [
+    'StaticXULComponentsEnd.cpp',
+]
+
+# Don't let LTO reorder StaticXULComponentsStart.o.
+if '-flto' in CONFIG['OS_CXXFLAGS']:
+    SOURCES['StaticXULComponentsEnd.cpp'].flags += ['-fno-lto']
+
+Library('StaticXULComponentsEnd')
+
+DEFINES['MOZILLA_INTERNAL_API'] = True