package/ghostscript: fix parallel build

Fixes:
 - http://autobuild.buildroot.org/results/eb33b41d1b267d0207a6e3a9f5ca7f79b2f51887

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
1 file changed