foomatic-filters: add -fcommon workaround

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

pkgs/misc/drivers/foomatic-filters/default.nix

@@ -25,6 +25,12 @@ stdenv.mkDerivation rec {
       substituteInPlace foomaticrip.c --replace /bin/bash ${stdenv.shell}
     '';
 
+  # 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
+  NIX_CFLAGS_COMPILE = "-fcommon";
+
   installTargets = [ "install-cups" ];
 
   installFlags = [