set gcc compiler

appveyor.yml

@@ -11,10 +11,30 @@ platform:
 init:
   - git config --global core.autocrlf input
 
+environment:
+  matrix:
+    - cmake: 1
+    # - variant: test_debug
+    #   compiler: msvc-14.0
+    #   model: 32
+    #   bjam: 1
+    # - variant: test_release
+    #   compiler: msvc-14.0
+    #   model: 64
+    #   python: 1
+    #   crypto: openssl
+    #   bjam: 1
+    - variant: test_debug
+      compiler: gcc
+      model: 64
+      crypto: openssl
+      bjam: 1
+
 install:
   - ps: Install-Product node 12 x64
   - git submodule update --init --recursive
   - choco install ninja
+  - g++ --version
   - cd %APPVEYOR_BUILD_FOLDER%\bindings\lib\libtorrent
   - mkdir build && cd build
   - cmake -DCMAKE_BUILD_TYPE=Release -DCMAKE_CXX_STANDARD=14 -G Ninja ..