configure: typo in detection of clang version.
configure: typo in detection of clang version.

gerdstolpmann/ocaml,eliberis/ocaml,yunxing/ocaml,gerdstolpmann/ocaml,msprotz/ocaml,yunxing/ocaml,yunxing/ocaml,eliberis/ocaml,eliberis/ocaml,yunxing/ocaml,gerdstolpmann/ocaml,yunxing/ocaml,gerdstolpmann/ocaml,gerdstolpmann/ocaml,msprotz/ocaml,eliberis/ocaml,msprotz/ocaml,eliberis/ocaml,msprotz/ocaml,msprotz/ocaml