Bug 1020165 - Remove empty makefiles; r=mshal

Makefile.in

@@ -294,7 +294,6 @@ ifdef MOZ_PSEUDO_DERECURSE
 # Interdependencies for parallel export.
 js/xpconnect/src/export: dom/bindings/export xpcom/xpidl/export
 accessible/src/xpcom/export: xpcom/xpidl/export
-js/src/export: mfbt/export
 ifdef ENABLE_CLANG_PLUGIN
 js/src/export config/export: build/clang-plugin/export
 endif

mfbt/Makefile.in

@@ -1,3 +0,0 @@
-# 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/.

mobile/android/fonts/Makefile.in

@@ -1,6 +0,0 @@
-# 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 $(topsrcdir)/config/rules.mk
-include $(topsrcdir)/testing/testsuite-targets.mk