hg: jdk/jdk: 8209115: adjust libsplashscreen linux ppc64le builds for easier libpng update

[matthias.baesken at sap.com]

Changeset: 9fe4fc157f4e
Author:    mbaesken
Date:      2018-08-10 09:16 +0200
URL:       http://hg.openjdk.java.net/jdk/jdk/rev/9fe4fc157f4e

8209115: adjust libsplashscreen linux ppc64le builds for easier libpng update
Reviewed-by: prr, dholmes

! make/lib/Awt2dLibraries.gmk
! src/java.desktop/share/native/libsplashscreen/libpng/pngpriv.h