RFR: JDK-8217032: Check pandoc capabilities in configure

[Mikael Vidstedt]

Looks good.

Cheers,
Mikael

> On Feb 14, 2019, at 3:26 PM, Erik Joelsson <erik.joelsson at oracle.com> wrote:
> 
> Please review this minor fix. The JDK build now has support for generating man pages, and will try to do so if it finds pandoc on the system. Unfortunately, not all versions of pandoc are valid, and if a bad version is found, the build will fail. This patch adds an extensions check for the found pandoc in configure, and if the "smart" extension that we use is missing, pandoc is disabled.
> 
> Bug: https://bugs.openjdk.java.net/browse/JDK-8217032
> 
> Webrev: http://cr.openjdk.java.net/~erikj/8217032/webrev.01/
> 
> /Erik
>