I incorporated two patches into my local meta-java layer. Then openjre-14 builds also!
diff --git a/recipes-core/openjdk/openjdk-14-common.inc b/recipes-core/openjdk/openjdk-14-common.inc
index 36451b8..df99626 100644
--- a/recipes-core/openjdk/openjdk-14-common.inc
+++ b/recipes-core/openjdk/openjdk-14-common.inc
@@ -30,6 +30,8 @@ SRC_URI = "\
https://hg.openjdk.java.net/jdk-updates/jdk14u/archive/jdk-${PV}-ga.tar.bz2;name=jdk \
file://0001-make-autoconf-remove-hard-dependency-on-cups.patch \
file://0002-make-autoconf-toolchain-remove-invalid-compiler-chec.patch \
+ file://0066-autoconf-fix-build-aux-path.patch \
+ file://0067-sysctl-path-fix.patch \
"
cat patches-openjdk-14/0066-autoconf-fix-build-aux-path.patch
diff --color -Nur jdk14u-jdk-14.0.1-ga.ORIG/make/autoconf/configure.ac jdk14u-jdk-14.0.1-ga/make/autoconf/configure.ac
--- jdk14u-jdk-14.0.1-ga.ORIG/make/autoconf/configure.ac 2020-03-05 13:10:05.000000000 +0100
+++ jdk14u-jdk-14.0.1-ga/make/autoconf/configure.ac 2021-03-20 15:59:41.985648025 +0100
@@ -33,7 +33,7 @@
AC_PREREQ([2.69])
AC_INIT(OpenJDK, openjdk, build-dev@openjdk.java.net,,http://openjdk.java.net)
-AC_CONFIG_AUX_DIR([$TOPDIR/make/autoconf/build-aux])
+AC_CONFIG_AUX_DIR([build-aux])
m4_include([build-aux/pkg.m4])
# Include these first...
cat patches-openjdk-14/0067-sysctl-path-fix.patch
diff --color -Nur jdk14u-jdk-14.0.1-ga.ORIG/src/jdk.incubator.jpackage/unix/native/libapplauncher/PosixPlatform.cpp jdk14u-jdk-14.0.1-ga/src/jdk.incubator.jpackage/unix/native/libapplauncher/PosixPlatform.cpp
--- jdk14u-jdk-14.0.1-ga.ORIG/src/jdk.incubator.jpackage/unix/native/libapplauncher/PosixPlatform.cpp 2020-03-05 13:10:05.000000000 +0100
+++ jdk14u-jdk-14.0.1-ga/src/jdk.incubator.jpackage/unix/native/libapplauncher/PosixPlatform.cpp 2021-03-20 19:15:37.959412799 +0100
@@ -33,7 +33,7 @@
#include <stdbool.h>
#include <sys/types.h>
#include <unistd.h>
-#include <sys/sysctl.h>
+#include <linux/sysctl.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <sys/wait.h>