Bug 1520177 - Fixed MinGW build's accessibility r=froydnj

This patch contains three fixes.

1) As in Bug 1515982, we use the constant for RT_MANIFEST instead of
the define, which needs winuser.rh to be included

2) We stop exempting the mingw builds from RCINCLUDE in
toolkit/library/moz.build which causes us to miss all of the
resources in xul.dll

3) We explicitly include IA2Marshal.dll instead of relying on
compiler magic to include it for us.

Differential Revision: https://phabricator.services.mozilla.com/D26295

--HG--
extra : moz-landing-system : lando

accessible/interfaces/ia2/IA2Marshal.rc

@@ -3,3 +3,4 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 1 typelib IA2Typelib.tlb
+2 24 IA2Marshal.dll.manifest

toolkit/library/moz.build

@@ -47,7 +47,7 @@ def Libxul(name, output_category=None):
     if CONFIG['OS_ARCH'] == 'WINNT' and CONFIG['ACCESSIBILITY']:
         LOCAL_INCLUDES += ['!/accessible/interfaces/gecko/']
 
-    if CONFIG['OS_ARCH'] == 'WINNT' and CONFIG['CC_TYPE'] not in ('clang', 'gcc'):
+    if CONFIG['OS_ARCH'] == 'WINNT':
         LOCAL_INCLUDES += [
             '/widget/windows',
             '/xpcom/base',

toolkit/library/xulrunner.rc

@@ -6,8 +6,8 @@
 #include "widget.rc"
 #ifdef ACCESSIBILITY
 1 typelib IGeckoCustom.tlb
-64 RT_MANIFEST IAccessible64.manifest
+64 24 IAccessible64.manifest
 #ifndef HAVE_64BIT_BUILD
-32 RT_MANIFEST IAccessible32.manifest
+32 24 IAccessible32.manifest
 #endif
 #endif