diff --git a/appveyor.yml b/appveyor.yml
index f10078fdd..bf982199b 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -28,9 +28,19 @@ environment:
       MINGW_CHOST: i686-w64-mingw32
       MSYS2_ARCH: i686
 
+    - compiler: cygwin
+      CYGWIN_PREFIX: C:\Cygwin64
+      CYGWIN_ARCH: x86_64
+   # Lots of test failures here!
+   #- compiler: cygwin
+   #  CYGWIN_PREFIX: C:\Cygwin
+   #  CYGWIN_ARCH: x86
+
+
 install:
   - 'if "%compiler%"=="msys2" C:\msys64\usr\bin\bash -lc "pacman --force --noconfirm -Sy && pacman --noconfirm --force -S pacman-mirrors && pacman --force -Syu --noconfirm"'
   - C:\msys64\usr\bin\bash -lc "pacman --noconfirm -S mingw-w64-x86_64-ragel"
+  - 'if "%compiler%"=="cygwin" %CYGWIN_PREFIX%\setup-%CYGWIN_ARCH%.exe -g -q -P cygwin-devel,libfreetype-devel,libcairo-devel,libicu-devel,gcc,gcc-g++,gobject-introspection,libglib2.0-devel,libgraphite2-devel,pkg-config,python2'
 
 build_script:
   - 'if "%compiler%"=="msvc" if not "%platform%"=="ARM" vcpkg install glib:%triplet% freetype:%triplet% cairo:%triplet%'
@@ -49,8 +59,13 @@ build_script:
   - 'if "%compiler%"=="msys2" C:\msys64\usr\bin\bash -lc "curl https://raw.githubusercontent.com/mirror/mingw-w64/023eb04c396d4e8d8fcf604cfababc53dae13398/mingw-w64-headers/include/dwrite_1.h > %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"'
 
+  - 'if "%compiler%"=="cygwin" set PATH=%PATH%;c:\msys64\mingw64\bin' # msys2 is added just for having "ragel" on PATH
+  - 'if "%compiler%"=="cygwin" curl https://raw.githubusercontent.com/mirror/mingw-w64/023eb04c396d4e8d8fcf604cfababc53dae13398/mingw-w64-headers/include/dwrite_1.h -o %CYGWIN_PREFIX%\usr\include\dwrite_1.h'
+  - 'if "%compiler%"=="cygwin" %CYGWIN_PREFIX%\bin\bash -lc "cd $APPVEYOR_BUILD_FOLDER; ./autogen.sh --with-uniscribe --with-freetype --with-glib --with-gobject --with-cairo --with-icu --with-graphite2 --with-directwrite; make; make check || .ci/fail.sh"'
+
 cache:
   - c:\tools\vcpkg\installed\
+  - '%CYGWIN_PREFIX%\var\cache\setup'
 
 notifications:
   - provider: Email
diff --git a/src/hb-blob.cc b/src/hb-blob.cc
index edee67300..368491c05 100644
--- a/src/hb-blob.cc
+++ b/src/hb-blob.cc
@@ -487,8 +487,8 @@ hb_blob_t::try_make_writable (void)
 #if defined(_WIN32) || defined(__CYGWIN__)
 # include <windows.h>
 #else
-# ifndef _O_BINARY
-#  define _O_BINARY 0
+# ifndef O_BINARY
+#  define O_BINARY 0
 # endif
 #endif
 
@@ -540,7 +540,7 @@ hb_blob_create_from_file (const char *file_name)
   hb_mapped_file_t *file = (hb_mapped_file_t *) calloc (1, sizeof (hb_mapped_file_t));
   if (unlikely (!file)) return hb_blob_get_empty ();
 
-  int fd = open (file_name, O_RDONLY | _O_BINARY, 0);
+  int fd = open (file_name, O_RDONLY | O_BINARY, 0);
   if (unlikely (fd == -1)) goto fail_without_close;
 
   struct stat st;
diff --git a/util/options.hh b/util/options.hh
index 3749b99be..dd628590e 100644
--- a/util/options.hh
+++ b/util/options.hh
@@ -586,7 +586,7 @@ struct output_options_t : option_group_t
       if (output_format)
       {
 	  output_format++; /* skip the dot */
-	  output_format = strdup (output_format);
+	  output_format = g_strdup (output_format);
       }
     }