package/lcdproc: fix musl build

Fixes
http://autobuild.buildroot.net/results/9ce/9cec3bea99f2aa10313da38c1e81655666c774f7/
http://autobuild.buildroot.net/results/b3d/b3d09286d018e53a6d57f8dd5616010a3b212731/
http://autobuild.buildroot.net/results/aa2/aa27b150a79b14fe1dda74a56371b4ee35b3ac15/


and others

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Reviewed-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>