Fix cygwin builds on appveyor
diff --git a/build/appveyor/CYGW-appveyor-build.bat b/build/appveyor/CYGW-appveyor-build.bat
index fbcc84b..7f33287 100644
--- a/build/appveyor/CYGW-appveyor-build.bat
+++ b/build/appveyor/CYGW-appveyor-build.bat
@@ -23,11 +23,13 @@
-G'%GENERATOR%' ^
-DCMAKE_BUILD_TYPE=%CONFIGURATION% ^
-DCMAKE_INSTALL_PREFIX=%INSTDIR% ^
- -DCMAKE_CXX_EXTENSIONS=ON ^
-DCMAKE_CXX_FLAGS="-D_GNU_SOURCE" ^
- -DCMAKE_CXX_STANDARD=11 ^
+ -DWITH_JAVA=OFF ^
-DWITH_PYTHON=OFF
+:: -DCMAKE_CXX_EXTENSIONS=ON ^
+:: -DCMAKE_CXX_STANDARD=11 ^
+
@ECHO ON
%BASH% -lc "mkdir -p %BUILDDIR% && cd %BUILDDIR% && cmake.exe %SRCDIR% %CMAKEARGS% && cmake --build . --config %CONFIGURATION% --target install" || EXIT /B
@ECHO OFF
diff --git a/build/appveyor/CYGW-appveyor-install.bat b/build/appveyor/CYGW-appveyor-install.bat
index 77db7d4..79b6ef0 100644
--- a/build/appveyor/CYGW-appveyor-install.bat
+++ b/build/appveyor/CYGW-appveyor-install.bat
@@ -31,4 +31,14 @@
%BASH% -lc "wget rawgit.com/transcode-open/apt-cyg/master/apt-cyg && install apt-cyg /bin && rm -f apt-cyg" || EXIT /B
%BASH% -lc "apt-cyg update" || EXIT /B
-%BASH% -lc "apt-cyg install bison cmake flex gcc-g++ libboost-devel libevent-devel make openssl-devel zlib-devel"
+%BASH% -lc "apt-cyg install bison cmake flex gcc-g++ libboost-devel libevent-devel make openssl-devel xz zlib-devel"
+
+::
+:: We need a newer version of cmake, the one cygwin provides is too old
+:: to recognize the version of boost. Luckily there is a pre-release
+:: one available, however cygwin's own setup program has no command line
+:: option to allow access to test packages!
+::
+
+%BASH% -lc "apt-cyg remove cmake"
+%BASH% -lc "cd / && wget http://mirror.clarkson.edu/cygwin/x86_64/release/cmake/cmake-3.13.1-1.tar.xz && tar xJf cmake-3.13.1-1.tar.xz && hash -r && cmake --version"