Create CMake instance and execute configure step

def configure_cmake(self):
        """Create CMake instance and execute configure step
        """
        cmake = CMake(self)
        cmake.definitions["FLATBUFFERS_BUILD_TESTS"] = False
        cmake.definitions["FLATBUFFERS_BUILD_SHAREDLIB"] = self.options.shared
        cmake.definitions["FLATBUFFERS_BUILD_FLATLIB"] = not self.options.shared
        cmake.configure()
        return cmake