[CMake] How to avoid -${MAKEFLAGS} in the CMAKE generated Makefiles ?

[Xiangyun Kong]

I am getting some problems in using CMAKE on windows. With CMAKE
generated Makefiles, when I use gnu make, I am getting the following errors,

NMAKE : fatal error U1065: invalid option '-'

It seems the -$(MAKEFLAGS) on the Make command options 
lead to the problem. The MAKEFLAGS is not defined in my environemtn,
and for some reasons, the CMAKE generated Makefile puts the 
$(MAKEFLAGS) as an option.

Any hints on getting rid of it would be appreciated.

TIA.

Xiangyun