This is derived from the pkgsrc-joyent set for openjdk11
https://github.com/joyent/pkgsrc-joyent/tree/master/openjdk11

All patches -p0

This set of patches for jdk11u

11.0.20

Minor patch update needed in Awt2dLibraries.gmk

11.0.19

Rework of the way the build and target OS is identified.

11.0.16

Fix the memcntl signature for recent illumos changes.

11.0.13

Just a little patch noise to tidy up

11.0.12 - remove illumos-cpu_microcode_revision.patch, there's an
equivalent stub fix applied upstream so we don't need to do it

Removed:

patch-make_autoconf_flags-other.m4 - breaks as
patch-make_autoconf_lib-bundled.m4 - breaks zlib
patch-make_lib_Lib-java.instrument.gmk - remove -liconv
patch-make_lib_Lib-jdk.jdwp.agent.gmk - remove -liconv
patch-make_autoconf_flags-ldflags.m4 - broken as of 11.0.7

Modified:

patch-make_lib_Awt2dLibraries.gmk - remove -liconv
patch-make_launcher_LauncherCommon.gmk - breaks zlib
patch-make_launcher_Launcher-jdk.pack.gmk - breaks zlib

Anything named tribblix* is my additional patches:

tribblix-attachListener_solaris.patch
  fixes incorrect arguments

tribblix-flags-cflags.patch 
  remove SSP

tribblix-Launcher-jdk.patch
tribblix-LauncherCommon.patch
  KPIC -> fPIC

tribblix-agent-mt.patch
  remove -mt

tribblix-flags-ldflags.patch
tribblix-flags-ldflags2.patch
  replace the broken patch-make_autoconf_flags-ldflags.m4

tribblix-flags-ldflags3.patch
  don't use -pie or --allow-shlib-undefined

tribblix-demangle1.patch
tribblix-demangle2.patch
tribblix-demangle3.patch
tribblix-demangle4.patch
  use the gcc demangle rather than the Studio demangle

tribblix-sparc1.patch
  some basic fixes necessary (but not sufficient) for a SPARC build

tribblix-sparc2.patch
  fixes to enable a sparc build with gcc; it's possible that using the
  atomic_linux_sparc.hpp from linux_sparc rather than
  atomic_solaris_sparc.hpp from solaris_sparc may also be required 

Build:

Use a jdk11 build as a bootstrap (from Liberica or Azul should also
work if your distro doesn't have one yet).

env PATH=/usr/bin:/usr/sbin:/usr/sfw/bin:/usr/gnu/bin bash ./configure \
--enable-unlimited-crypto --with-boot-jdk=/usr/jdk/instances/jdk11 \
--with-native-debug-symbols=none \
--with-toolchain-type=gcc \
--disable-hotspot-gtest --disable-dtrace \
--disable-warnings-as-errors

env PATH=/usr/bin:/usr/sbin:/usr/sfw/bin:/usr/gnu/bin gmake all