Make CMake use of CompileShaders more robust

CMakeLists.txt

@@ -187,8 +187,7 @@ if (NOT USE_PREBUILT_SHADERS)
         MAIN_DEPENDENCY "${PROJECT_SOURCE_DIR}/Src/Shaders/CompileShaders.cmd"
         DEPENDS ${SHADER_SOURCES}
         COMMENT "Generating HLSL shaders..."
-        COMMAND set CompileShadersOutput=${COMPILED_SHADERS}
-        COMMAND CompileShaders.cmd > ${COMPILED_SHADERS}/compileshaders.log
+        COMMAND ${CMAKE_COMMAND} -E env CompileShadersOutput="${COMPILED_SHADERS}" CompileShaders.cmd > "${COMPILED_SHADERS}/compileshaders.log"
         WORKING_DIRECTORY "${PROJECT_SOURCE_DIR}/Src/Shaders"
         USES_TERMINAL)
 endif()