appceyor MinGW build

appveyor.yml

@@ -1,22 +1,14 @@
 version: '{build}'
 image: Visual Studio 2017
 
-configuration:
-- Release
-
-platform:
-- x64
-
 environment:
   matrix:
-  - arch: Win64
+    - COMPILER: MSVC15
+    - COMPILER: MinGW-w64
 
 install: git submodule update --init --recursive
 
-before_build:
-  cmd: cmake -G "Visual Studio 15 2017 Win64"   
-
-build:
-  project: c:\projects\tic-80\TIC-80.sln
-  verbosity: minimal
-  parallel: true
+build_script:
+  - if [%COMPILER%]==[MSVC15] cmake -G "Visual Studio 15 2017" -DCMAKE_BUILD_TYPE=MinSizeRel .
+  - if [%COMPILER%]==[MinGW-w64] cmake -G "MinGW Makefiles" -DCMAKE_BUILD_TYPE=MinSizeRel .
+  - cmake --build .