hg: jdk9/client/jdk: 8035341: Allow using a system installed libpng

[omajid at redhat.com]

Changeset: 5e503831b142
Author:    omajid
Date:      2014-02-20 10:07 -0500
URL:       http://hg.openjdk.java.net/jdk9/client/jdk/rev/5e503831b142

8035341: Allow using a system installed libpng
Reviewed-by: andrew, erikj, ihse, serb

! make/lib/Awt2dLibraries.gmk
! src/share/native/sun/awt/splashscreen/splashscreen_png.c