Autofs 5.1.2 switched to clock_gettime() unconditionally but didn't
check for the need of librt (glibc < 2.17) for it. Fixes:
http://autobuild.buildroot.net/results/0ab/0abd5476b39a6bd192b5e610006ed585ffb2e139/
Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
