java/openjdk11: add bootstrap and fix compilation for powerpc64 elfv2

Add bootstrap for powerpc64 elfv2.

Because of issue with macros in precompiled.hpp, --disable-precompiled-headers is necessary.

Since openjdk compiles for elfv1 by default on big-endian ppc64, use a patch to compile for elfv2.

I assume here that GCC will be used exclusively on ELFv1 systems and Clang on ELFv2.

PR: 243182
Approved by: glewis (maintainer)