--- a/build/moz.configure/toolchain.configure
+++ b/build/moz.configure/toolchain.configure
@@ -962,13 +962,15 @@ def wrap_system_includes(target, visibil
 
 set_define('HAVE_VISIBILITY_HIDDEN_ATTRIBUTE',
            depends(visibility_flags)(lambda v: bool(v) or None))
 set_define('HAVE_VISIBILITY_ATTRIBUTE',
            depends(visibility_flags)(lambda v: bool(v) or None))
 set_config('WRAP_SYSTEM_INCLUDES', wrap_system_includes)
 set_config('VISIBILITY_FLAGS', visibility_flags)
 
-@depends(target)
-def is_windows(target):
-    return target.kernel == 'WINNT'
+# We only want to include windows.configure when we are compiling on
+# Windows, for Windows.
+@depends(target, host)
+def is_windows(target, host):
+    return host.kernel == 'WINNT' and target.kernel == 'WINNT'
 
 include('windows.configure', when=is_windows)

--- a/old-configure.in
+++ b/old-configure.in
@@ -3113,29 +3113,31 @@ dnl ====================================
 MOZ_ARG_DISABLE_BOOL(universalchardet,
 [  --disable-universalchardet
                           Disable universal encoding detection],
   MOZ_UNIVERSALCHARDET=,
   MOZ_UNIVERSALCHARDET=1 )
 
 dnl ========================================================
 dnl = ANGLE OpenGL->D3D translator for WebGL
-dnl = * only applies to win32
+dnl = * only applies to win32 (and then, not MINGW)
 dnl ========================================================
 
 MOZ_ANGLE_RENDERER=
 MOZ_D3D_CPU_SUFFIX=
 MOZ_HAS_WINSDK_WITH_D3D=
 MOZ_D3DCOMPILER_VISTA_DLL=
 MOZ_D3DCOMPILER_VISTA_DLL_PATH=
 
 if test "$COMPILE_ENVIRONMENT" ; then
 case "$target_os" in
 *mingw*)
-    MOZ_ANGLE_RENDERER=1
+    if test "$OS_ARCH" = "$HOST_OS_ARCH"; then
+      MOZ_ANGLE_RENDERER=1
+    fi
     ;;
 esac
 
 # The DirectX SDK libraries are split into x86 and x64 sub-directories
 case "${target_cpu}" in
 i*86)
   MOZ_D3D_CPU_SUFFIX=x86
   ;;