hg: build-infra/jdk8/jdk: Back out changes from bb020964725b.

[magnus.ihse.bursie at oracle.com]

Changeset: 2c43a21f5f3e
Author:    ihse
Date:      2012-09-17 14:24 +0200
URL:       http://hg.openjdk.java.net/build-infra/jdk8/jdk/rev/2c43a21f5f3e

Back out changes from bb020964725b.

While that fix enabled cross-compilation on linux from x86 to x86_64, it
broke the build on several other platforms. Restore old behaviour until we
sort this out better.

! makefiles/GensrcX11Wrappers.gmk