lang/lci: fix build on -HEAD

• Add USES+= readline to work around readline removal from base, which causes build-issues on 11.0-CURRENT
• While there, remove GH_COMMIT

Spotted by: Maxim Filimonov <che@bein.link>
Differential Revision: https://reviews.freebsd.org/D2147
Approved by: koobs (mentor)