--- a/gfx/thebes/gfxDWriteFontList.h
+++ b/gfx/thebes/gfxDWriteFontList.h
@@ -13,17 +13,17 @@
  // Currently, we build with WINVER=0x601 (Win7), which means newer
  // declarations in dwrite_3.h will not be visible. Also, we don't
  // yet have the Fall Creators Update SDK available on build machines,
  // so even with updated WINVER, some of the interfaces we need would
  // not be present.
  // To work around this, until the build environment is updated,
  // we #include an extra header that contains copies of the relevant
  // classes/interfaces we need.
-#if WINVER < 0x0A00
+#if !defined(__MINGW32__) && WINVER < 0x0A00
 #include "dw-extra.h"
 #endif
 
 #include "gfxFont.h"
 #include "gfxUserFontSet.h"
 #include "cairo-win32.h"
 
 #include "gfxPlatformFontList.h"

--- a/taskcluster/scripts/misc/build-gcc-mingw32.sh
+++ b/taskcluster/scripts/misc/build-gcc-mingw32.sh
@@ -13,17 +13,17 @@ data_dir=$HOME_DIR/src/build/unix/build-
 
 . $data_dir/build-gcc.sh
 
 gcc_version=6.4.0
 gcc_ext=xz
 binutils_version=2.27
 binutils_ext=bz2
 binutils_configure_flags="--target=i686-w64-mingw32"
-mingw_version=8bcc70834969d34e113c5614364c4661cfa5d1be
+mingw_version=0720cca3532c32103d999754a734a79061a749a3
 
 # GPG keys used to sign GCC (collected from 5.1.0, 5.4.0, 6.4.0)
 $GPG --import $data_dir/33C235A34C46AA3FFB293709A328C3A2C3C45C06.key
 $GPG --import $data_dir/7F74F97C103468EE5D750B583AB00996FC26A641.key
 # GPG key used to sign binutils
 $GPG --import $data_dir/EAF1C276A747E9ED86210CBAC3126D3B4AE55E93.key
 # GPG key used to sign GMP
 $GPG --import $data_dir/343C2FF0FBEE5EC2EDBEF399F3599FF828C67298.key