lang/adacontrol: Upgrade version 1.17r3 => 1.18r9

The big feature for adacontrol 1.18 is the direct support of .gpr project
files. Unfortunately, the project support requires devel/gnatcoll, a heavy
dependency. Thus, a PROJECT option was created which is "OFF" by default to
maintain the relatively lean dependency requirements. If project support is
vital, reconfigure the build with the PROJECT option.