diff --git a/appveyor.yml b/appveyor.yml
index 5971337cd..b68572062 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -20,11 +20,11 @@ environment:
 
 
     - compiler: msys2
-      MINGW_PREFIX: /c/msys2/mingw64/
+      MINGW_PREFIX: /mingw64
       MINGW_CHOST: x86_64-w64-mingw32
       MSYS2_ARCH: x86_64
     - compiler: msys2
-      MINGW_PREFIX: /c/msys2/mingw32/
+      MINGW_PREFIX: /mingw32
       MINGW_CHOST: i686-w64-mingw32
       MSYS2_ARCH: i686
 
@@ -44,7 +44,8 @@ build_script:
   - 'if "%compiler%"=="msvc" if not "%platform%"=="ARM" ctest --output-on-failure -C %configuration%'
 
   - 'if "%compiler%"=="msys2" C:\msys64\usr\bin\bash -lc "pacman --noconfirm -S mingw-w64-$MSYS2_ARCH-{freetype,cairo,icu,gettext,gobject-introspection,gcc,gcc-libs,glib2,graphite2,pkg-config,python2}"'
-  - 'if "%compiler%"=="msys2" C:\msys64\usr\bin\bash -lc "cd $APPVEYOR_BUILD_FOLDER; PATH=$PATH:/mingw64/bin:/mingw32/bin; ./autogen.sh --with-uniscribe --with-freetype --with-glib --with-gobject --with-cairo --with-icu --with-graphite2 --build=%MINGW_CHOST% --host=%MINGW_CHOST% --prefix=%MINGW_PREFIX%; make; make check || .ci/fail.sh"'
+  - 'if "%compiler%"=="msys2" C:\msys64\usr\bin\bash -lc "curl https://sourceforge.net/p/mingw-w64/mingw-w64/ci/master/tree/mingw-w64-headers/include/dwrite_1.h?format=raw > %MINGW_PREFIX%/%MINGW_CHOST%/include/dwrite_1.h"'
+  - 'if "%compiler%"=="msys2" C:\msys64\usr\bin\bash -lc "cd $APPVEYOR_BUILD_FOLDER; PATH=$PATH:/mingw64/bin:/mingw32/bin; ./autogen.sh --with-uniscribe --with-freetype --with-glib --with-gobject --with-cairo --with-icu --with-graphite2 --with-directwrite --build=%MINGW_CHOST% --host=%MINGW_CHOST% --prefix=%MINGW_PREFIX%; make; make check || .ci/fail.sh"'
 
 cache:
   - c:\tools\vcpkg\installed\
diff --git a/src/hb-directwrite.cc b/src/hb-directwrite.cc
index 40e9e39bf..0d3b1c2e4 100644
--- a/src/hb-directwrite.cc
+++ b/src/hb-directwrite.cc
@@ -48,7 +48,7 @@ class DWriteFontFileLoader : public IDWriteFontFileLoader
 private:
   IDWriteFontFileStream *mFontFileStream;
 public:
-  void init (IDWriteFontFileStream *fontFileStream)
+  DWriteFontFileLoader (IDWriteFontFileStream *fontFileStream)
   {
     mFontFileStream = fontFileStream;
   }
@@ -74,7 +74,7 @@ private:
   uint8_t *mData;
   uint32_t mSize;
 public:
-  void init (uint8_t *aData, uint32_t aSize)
+  DWriteFontFileStream (uint8_t *aData, uint32_t aSize)
   {
     mData = aData;
     mSize = aSize;
@@ -151,14 +151,11 @@ _hb_directwrite_shaper_face_data_create(hb_face_t *face)
 
   HRESULT hr;
   hb_blob_t *blob = hb_face_reference_blob (face);
-  DWriteFontFileStream *fontFileStream = (DWriteFontFileStream*)
-    malloc (sizeof (DWriteFontFileStream));
-  fontFileStream->init ((uint8_t*) hb_blob_get_data (blob, nullptr),
+  DWriteFontFileStream *fontFileStream = new DWriteFontFileStream (
+    (uint8_t *) hb_blob_get_data (blob, nullptr),
     hb_blob_get_length (blob));
 
-  DWriteFontFileLoader *fontFileLoader = (DWriteFontFileLoader*)
-    malloc (sizeof (DWriteFontFileLoader));
-  fontFileLoader->init (fontFileStream);
+  DWriteFontFileLoader *fontFileLoader = new DWriteFontFileLoader (fontFileStream);
   dwriteFactory->RegisterFontFileLoader (fontFileLoader);
 
   IDWriteFontFile *fontFile;
@@ -216,9 +213,9 @@ _hb_directwrite_shaper_face_data_destroy(hb_directwrite_shaper_face_data_t *data
     data->dwriteFactory->Release ();
   }
   if (data->fontFileLoader)
-    free (data->fontFileLoader);
+    delete data->fontFileLoader;
   if (data->fontFileStream)
-    free (data->fontFileStream);
+    delete data->fontFileStream;
   if (data->faceBlob)
     hb_blob_destroy (data->faceBlob);
   if (data)
@@ -924,7 +921,7 @@ hb_directwrite_shape_experimental_width(hb_font_t          *font,
   unsigned int        num_features,
   float               width)
 {
-  static char *shapers = (char *) "directwrite";
+  static const char *shapers = "directwrite";
   hb_shape_plan_t *shape_plan = hb_shape_plan_create_cached (font->face,
     &buffer->props, features, num_features, &shapers);
   hb_bool_t res = _hb_directwrite_shape_full (shape_plan, font, buffer,