How do I configure the cross compilation toolchain

[chensisi0730]

./tools/waf configure --without-ipp
Setting top to : /home/css/work/FFT/sfft-0.1.0
Setting out to : /home/css/work/FFT/sfft-0.1.0/build
Checking for 'g++' (c++ compiler) : /usr/bin/g++
Checking for program pkg-config : /usr/bin/pkg-config
Checking for 'valgrind' : yes
Checking for 'fftw3' : yes
Checking for library m : yes
Checking for library rt : yes
Checking for library gomp : yes
Checking for compiler flags ['-O3', '-ffast-math', '-march=native', '-fopenmp'] : yes
Checking for compiler flags ['-Wall'] : yes
Checking for compiler flags ['-pg'] : yes
'configure' finished successfully (0.403s)

who can i configure g++ to my cross compilation toolchain ?