Most linking errors dealt with on compiling on MinGW

dom/canvas/WebGLContext.cpp

@@ -842,6 +842,13 @@ WebGLContext::ThrowEvent_WebGLContextCreationError(const nsACString& text)
     GenerateWarning("Failed to create WebGL context: %s", text.BeginReading());
 }
 
+NS_IMETHODIMP
+WebGLContext::InitializeWithDrawTarget(nsIDocShell*,
+                                       NotNull<gfx::DrawTarget*>)
+{
+    return NS_ERROR_NOT_IMPLEMENTED;
+}
+
 NS_IMETHODIMP
 WebGLContext::SetDimensions(int32_t signedWidth, int32_t signedHeight)
 {

dom/canvas/WebGLContext.h

@@ -347,10 +347,7 @@ public:
 
     NS_IMETHOD SetDimensions(int32_t width, int32_t height) override;
     NS_IMETHOD InitializeWithDrawTarget(nsIDocShell*,
-                                        NotNull<gfx::DrawTarget*>) override
-    {
-        return NS_ERROR_NOT_IMPLEMENTED;
-    }
+                                        NotNull<gfx::DrawTarget*>) override;
 
     NS_IMETHOD Reset() override {
         /* (InitializeWithSurface) */

gfx/gl/moz.build

@@ -20,6 +20,8 @@ elif 'gtk' in CONFIG['MOZ_WIDGET_TOOLKIT']:
 if CONFIG['MOZ_GL_PROVIDER']:
     gl_provider = CONFIG['MOZ_GL_PROVIDER']
 
+DISABLE_STL_WRAPPING = True
+
 EXPORTS += [
     'DecomposeIntoNoRepeatTriangles.h',
     'EGLUtils.h',

gfx/skia/moz.build

@@ -646,7 +646,10 @@ else:
 # We allow warnings for third-party code that can be updated from upstream.
 ALLOW_COMPILER_WARNINGS = True
 
-FINAL_LIBRARY = 'gkmedias'
+if CONFIG['GNU_CC']:
+    FINAL_LIBRARY = 'xul'
+else:
+    FINAL_LIBRARY = 'gkmedias'
 LOCAL_INCLUDES += [
     'skia/include/c',
     'skia/include/config',
@@ -697,6 +700,10 @@ if CONFIG['GKMEDIAS_SHARED_LIBRARY']:
     DEFINES['SKIA_DLL'] = 1
     DEFINES['GR_DLL'] = 1
     DEFINES['SK_FONT_HOST_USE_SYSTEM_SETTINGS'] = 1
+if CONFIG['GKMEDIAS_SHARED_LIBRARY'] and not CONFIG['GNU_CC']:
+    DEFINES['SKIA_DLL'] = 1
+    DEFINES['GR_DLL'] = 1
+    DEFINES['SK_FONT_HOST_USE_SYSTEM_SETTINGS'] = 1
 
 # We should autogenerate these SSE related flags.
 

memory/mozalloc/mozalloc_abort.h

@@ -16,7 +16,13 @@
  * Note: MOZ_NORETURN seems to break crash stacks on ARM, so we don't
  * use that annotation there.
  */
-MFBT_API
+#if defined(__MINGW32__)
+#  define MOZALLOC_ABORT_API
+#else
+#  define MOZALLOC_ABORT_API MFBT_API
+#endif
+
+MOZALLOC_ABORT_API
 #if !defined(__arm__)
   MOZ_NORETURN
 #endif

toolkit/library/nsDllMain.cpp

@@ -2,7 +2,8 @@
 /* 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 <stdlib.h>
 #include <windows.h>
 #include "nsToolkit.h"
 #include "mozilla/Assertions.h"