manaplus: add missing libX11

Grimmauld c4a55c2a db355161

+2
+2
pkgs/by-name/ma/manaplus/package.nix
··· 13 curl, 14 libxml2, 15 libpng, 16 pkg-config, 17 libGL, 18 autoreconfHook, ··· 53 curl 54 libGL 55 libpng 56 libxml2 57 physfs 58 zlib
··· 13 curl, 14 libxml2, 15 libpng, 16 + libX11, 17 pkg-config, 18 libGL, 19 autoreconfHook, ··· 54 curl 55 libGL 56 libpng 57 + libX11 58 libxml2 59 physfs 60 zlib