Update build shell scripts to use premake5 `gmake2.*` directories. (The old `gmake.*` directories have been removed from premake5.) Differential Revision: https://code.wildfiregames.com/D3219 This was SVN commit r24388.
Update build shell scripts to use premake5 `gmake2.*` directories. (The old `gmake.*` directories have been removed from premake5.) Differential Revision: https://code.wildfiregames.com/D3219 This was SVN commit r24388.