add github actions workflow & disable gcc9 warnings

Additional: disable initializer list warning

.github/workflows/linux.yml

@@ -0,0 +1,23 @@
+name: Linux
+
+on: [push]
+env:
+  # Customize the CMake build type here (Release, Debug, RelWithDebInfo, etc.)
+  BUILD_TYPE: Release
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+    - uses: seanmiddleditch/gha-setup-ninja@master
+
+    - name: Configure CMake
+      run: cmake -B ${{github.workspace}}/build -DCMAKE_BUILD_TYPE=${{env.BUILD_TYPE}} -DBUILD_EXAMPLES=OFF -G Ninja
+
+    - name: Build
+      run: cmake --build ${{github.workspace}}/build
+
+    - name: Test
+      run: cmake --build ${{github.workspace}}/build --target run_tests

src/rttr/detail/base/core_prerequisites.h

@@ -278,6 +278,15 @@ namespace rttr
 #   define RTTR_END_DISABLE_OVERRIDE_WARNING
 #endif
 
+#if RTTR_COMP_VER >= 900
+#   define RTTR_BEGIN_DISABLE_INIT_LIST_WARNING       _Pragma ("GCC diagnostic push") \
+                                                      _Pragma ("GCC diagnostic ignored \"-Winit-list-lifetime\"")
+#   define RTTR_END_DISABLE_INIT_LIST_WARNING         _Pragma ("GCC diagnostic pop")
+# else
+#   define RTTR_BEGIN_DISABLE_INIT_LIST_WARNING
+#   define RTTR_END_DISABLE_INIT_LIST_WARNING
+#endif
+
 #   define RTTR_DECLARE_PLUGIN_CTOR       __attribute__((constructor))
 #   define RTTR_DECLARE_PLUGIN_DTOR       __attribute__((destructor))
 
@@ -313,6 +322,10 @@ namespace rttr
 #   define RTTR_END_DISABLE_OVERRIDE_WARNING
 #endif
 
+
+#   define RTTR_BEGIN_DISABLE_INIT_LIST_WARNING
+#   define RTTR_END_DISABLE_INIT_LIST_WARNING
+
 #   define RTTR_DECLARE_PLUGIN_CTOR        __attribute__((__constructor__))
 #   define RTTR_DECLARE_PLUGIN_DTOR        __attribute__((__destructor__))
 
@@ -332,6 +345,8 @@ namespace rttr
 #   define RTTR_DECLARE_PLUGIN_DTOR
 #   define RTTR_BEGIN_DISABLE_OVERRIDE_WARNING
 #   define RTTR_END_DISABLE_OVERRIDE_WARNING
+#   define RTTR_BEGIN_DISABLE_INIT_LIST_WARNING
+#   define RTTR_END_DISABLE_INIT_LIST_WARNING
 
 #else
 #   pragma message("WARNING: unknown compiler, don't know how to disable deprecated warnings")

src/rttr/detail/variant/variant_data_policy.h

@@ -434,7 +434,7 @@ struct variant_data_policy_big : variant_data_base_policy<T, variant_data_policy
     {
         delete &value;
     }
-
+RTTR_BEGIN_DISABLE_INIT_LIST_WARNING
     static RTTR_INLINE void clone(const T& value, variant_data& dest)
     {
         reinterpret_cast<T*&>(dest) = new T(value);
@@ -450,6 +450,7 @@ struct variant_data_policy_big : variant_data_base_policy<T, variant_data_policy
     {
         reinterpret_cast<T*&>(dest) = new T(std::forward<U>(value));
     }
+RTTR_END_DISABLE_INIT_LIST_WARNING
 };
 
 /////////////////////////////////////////////////////////////////////////////////////////