gcc -o inex-glinfo glinfo.c -O2 -lX11 -lGL -lXext

/usr/bin/ld: cannot find -lGL
/usr/bin/ld: cannot find -lXext
collect2: error: ld returned 1 exit status
make[1]: *** [make] Error 1
make[1]: Leaving directory
`/build/buildd/i-nex-0.6.2+bzr531+20140127~ubuntu14.04.1'
dh_auto_build: make -j1 returned exit code 2
make: *** [build-arch] Error 2
dpkg-buildpackage: error: debian/rules build-arch gave error exit status 2