hg: panama/dev: Summary: Add libclang version check and option to select version

[jbvernee at xs4all.nl]

Changeset: 819585c6b8e3
Author:    jvernee
Date:      2019-05-07 18:51 +0200
URL:       http://hg.openjdk.java.net/panama/dev/rev/819585c6b8e3

Summary: Add libclang version check and option to select version
Reviewed-by: mcimadamore

! make/autoconf/lib-clang.m4