# the alternatives are far, far worse.
if ("${CMAKE_GENERATOR}" MATCHES "Visual Studio 15( 2017)? Win64")
set(CMAKE_GENERATOR_TOOLSET "v141</PlatformToolset></PropertyGroup><ItemDefinitionGroup Condition=\"'$(ProjectName)'=='folly'\"><ProjectReference><LinkLibraryDependencies>true</LinkLibraryDependencies></ProjectReference></ItemDefinitionGroup><PropertyGroup><PlatformToolset>v141")
+ set(MSVC_IS_2017 ON)
elseif ("${CMAKE_GENERATOR}" STREQUAL "Visual Studio 14 2015 Win64")
set(CMAKE_GENERATOR_TOOLSET "v140</PlatformToolset></PropertyGroup><ItemDefinitionGroup Condition=\"'$(ProjectName)'=='folly'\"><ProjectReference><LinkLibraryDependencies>true</LinkLibraryDependencies></ProjectReference></ItemDefinitionGroup><PropertyGroup><PlatformToolset>v140")
+ set(MSVC_IS_2017 OFF)
else()
message(FATAL_ERROR "This build script only supports building Folly on 64-bit Windows with Visual Studio 2015 or Visual Studio 2017.")
endif()