CMake´s buildscript generator to use (e.g. Unix Makefiles).
Possible generators include:

The build tool chosen by CMake corresponds to the specified script generator and is exposed in the CMAKE_BUILD_TOOL build environment variable for any generator except the Visual Studio and Xcode generators (these generators do not set CMAKE_MAKE_PROGRAM at buildscript generation time).
The actual value of CMAKE_BUILD_TOOL is retrieved from the generated CMake cache file (CMakeCache.txt).
Subsequent build steps may use ${CMAKE_BUILD_TOOL} to execute the generated scripts.

HINT: This field does not require quotes if the name of the generator contains spaces.