[foreign-jextract] RFR: configure should fail if libclang path is not specified

[Chris Hegarty]

On Fri, 29 May 2020 12:36:05 GMT, Athijegannathan Sundararajan <sundar at openjdk.org> wrote:

> configure fails after the message rather than continuging after warning

Looks good to me.

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Marked as reviewed by chegar (no project role).

PR: https://git.openjdk.java.net/panama-foreign/pull/190