How to install LIBSVM in Matlab

I have followed the instructions to LIBSVM in Matlab. However, at the final, when I typed" make" and pressed enter, it shown an error message "C:\MATLAB7\BIN\WIN32\MEX.PL: Error: 'CFLAGS=\$CFLAGS -std=c99' not found. If make.m fails, please check README about detailed instructions"

Does anyone know why it happened and how to solve it? Thank you

[Walter Roberson]

Did you use

mex -setup

first?