RFR(T): 8221434: Fix typo in lib-x11 autoconf error message about missing headers

[David Holmes]

Looks good Gustavo.

Thanks,
David

On 26/03/2019 9:53 am, Gustavo Romero wrote:
> Hi,
> 
> Could the following trivial change be reviewed, please?
> 
> bug    : https://bugs.openjdk.java.net/browse/JDK-8221434
> webrev : http://cr.openjdk.java.net/~gromero/8221434/v1/
> 
> Thank you and best regards,
> Gustavo
>