CMAKE_VS_PLATFORM_TOOLSET might be empty (simdjson#1009)

myd7349 · web-flow · commit cc042c99369d · 2020-06-30T09:40:19.000-04:00
According to https://gitlab.kitware.com/cmake/cmake/-/issues/17976, CMAKE_VS_PLATFORM_TOOLSET is set only when using a Visual Studio generator. When we use Ninja as the generator, CMAKE_VS_PLATFORM_TOOLSET will be empty. As a result: if(${CMAKE_VS_PLATFORM_TOOLSET} STREQUAL "v140") will be treated as: if( STREQUAL "v140") We may also quote it like this: if("${CMAKE_VS_PLATFORM_TOOLSET}" STREQUAL "v140") but that won't make the warnings disappeared in VS2015.
diff --git a/cmake/simdjson-flags.cmake b/cmake/simdjson-flags.cmake
@@ -77,7 +77,7 @@ set(THREADS_PREFER_PTHREAD_FLAG ON)
 
 
 if(MSVC)
-if(${CMAKE_VS_PLATFORM_TOOLSET} STREQUAL "v140")
+if("${MSVC_TOOLSET_VERSION}" STREQUAL "140")
   # Visual Studio 2015 issues warnings and we tolerate it,  cmake -G"Visual Studio 14" ..
   target_compile_options(simdjson-internal-flags INTERFACE /W0 /sdl)
 else()
