kc3-lang/sys_wait

diff --git a/appveyor.yml b/appveyor.yml
index fe7319c..9bf6c36 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -7,6 +7,9 @@ environment:
           CMAKE_GENERATOR: "MinGW Makefiles"
           MINGW_HOME: "C:\\mingw-w64\\x86_64-7.2.0-posix-seh-rt_v5-rev1\\mingw64\\bin"
         - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
+          CMAKE_GENERATOR: "Ninja"
+          CC: "C:\\Program Files\\LLVM\\bin\\clang-cl.exe"
+        - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
           CMAKE_GENERATOR: "Visual Studio 12 2013"
         - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
           CMAKE_GENERATOR: "Visual Studio 12 2013 Win64"
@@ -19,5 +22,11 @@ environment:
         - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
           CMAKE_GENERATOR: "Visual Studio 15 2017 Win64"
 
+install:
+    - mkdir C:\ninja
+    - appveyor DownloadFile https://github.com/ninja-build/ninja/releases/download/v1.9.0/ninja-win.zip -FileName ninja.zip
+    - 7z x ninja.zip -oC:\ninja > nul
+    - set PATH=C:\ninja;%PATH%
+
 test_script:
     - python build.py