RFR: JDK-8026888: Licensee build failure due to wrong libs being called

[Tim Bell]

Hi Erik:

> This patch removes the last reference to OPENWIN on linux. All other 
> libs were already converted to using X_LIBS and X_CFLAGS instead of 
> OPENWIN_HOME on linux, but libsplashscreen was still using OPENWIN. I 
> also removed the logic in configure that probed for it.
>
> Bug: https://bugs.openjdk.java.net/browse/JDK-8026888
>
> Webrev: http://cr.openjdk.java.net/~erikj/8026888/webrev.01

Looks good.

/Tim