cmake 指定gcc路径
export CC=/usr/local/bin/gcc
export CXX=/usr/local/bin/g++
export LD_LIBRARY_PATH=/usr/local/gcc-4.7.2/lib:$LD_LIBRARY_PATH
cmake /path/to/your/project make
export CC=/usr/local/bin/gcc
export CXX=/usr/local/bin/g++
export LD_LIBRARY_PATH=/usr/local/gcc-4.7.2/lib:$LD_LIBRARY_PATH
cmake /path/to/your/project make