Workaround build failure on -fno-common toolchains like upstream
gcc-10. Otherwise build fails as:
ld: foomatic_rip-options.o:/build/foomatic-filters-4.0.17/options.c:49: multiple definition of
`cupsfilter'; foomatic_rip-foomaticrip.o:/build/foomatic-filters-4.0.17/foomaticrip.c:158: first defined here