make PREFIX=$PREFIX CXXFLAGS="-I$PREFIX/include -L$PREFIX/lib $CXXFLAGS"
make install PREFIX=$PREFIX

make PREFIX=$PREFIX LDFLAGS="-L$PREFIX/lib" CXXFLAGS="-I$PREFIX/include $CXXFLAGS"
make install PREFIX=$PREFIX

Use LDFLAGS instead of CXXFLAGS
Use LDFLAGS instead of CXXFLAGS
