appveyor: Use ccache

Reduces i686 cygwin no-change build time from ~7 minutes to ~2.5 minutes

.appveyor.yml

@@ -5,18 +5,22 @@ version: '{build}'
 skip_tags: true
 clone_depth: 8
 environment:
+  APPVEYOR_SAVE_CACHE_ON_ERROR: true
   CYGWIN_MIRROR: http://cygwin.mirror.constant.com
   CACHE: C:\cache
   matrix:
   - BUILD: i686-pc-cygwin
+    CYGWIN_ROOT: C:\cygwin
+    SETUP: setup-x86.exe
   - BUILD: x86_64-pc-cygwin
+    CYGWIN_ROOT: C:\cygwin64
+    SETUP: setup-x86_64.exe
 install:
-- if "%BUILD%"=="x86_64-pc-cygwin" set SETUP=setup-x86_64.exe && set CYGWIN_ROOT=C:\cygwin64
-- if "%BUILD%"=="i686-pc-cygwin" set SETUP=setup-x86.exe && set CYGWIN_ROOT=C:\cygwin
 - echo Updating Cygwin and installing build prerequisites
 - "%CYGWIN_ROOT%\\%SETUP% -qnNdO -R %CYGWIN_ROOT% -s %CYGWIN_MIRROR% -l %CACHE% -g -P \
 binutils,\
 bison,\
+ccache,\
 flex,\
 gcc-core,\
 meson,\
@@ -66,11 +70,13 @@ xtrans"
 - echo Install done
 cache:
 - C:\cache
+- '%CYGWIN_ROOT%\home\%USERNAME%\.ccache'
 build_script:
 - SET PATH=%CYGWIN_ROOT%/bin
 - '%CYGWIN_ROOT%/bin/bash -lc "cd $APPVEYOR_BUILD_FOLDER; meson setup --prefix=/usr -Dxv=false -Dxf86bigfont=true -Ddmx=true -Dxephyr=true -Dxnest=true -Dxvfb=true -Dxwin=true -Dxorg=true -Dhal=false -Dudev=false -Dpciaccess=false -Dint10=false build"'
 - '%CYGWIN_ROOT%/bin/bash -lc "cd $APPVEYOR_BUILD_FOLDER; meson configure build"'
 - '%CYGWIN_ROOT%/bin/bash -lc "cd $APPVEYOR_BUILD_FOLDER; ninja -C build"'
+- '%CYGWIN_ROOT%/bin/bash -lc "cd $APPVEYOR_BUILD_FOLDER; ccache -s"'
 test_script:
 - '%CYGWIN_ROOT%/bin/bash -lc "cd $APPVEYOR_BUILD_FOLDER; ninja -C build test"'
 after_test: