dev-java/openjdk: mark as LTO-unsafe

Temporarily disable the USE=lto support for the 21.x ebuild only, as
that's the version it broke in.

OpenJDK cannot get their act together, so their ticketing system is
that you cannot report a bug unless you're a project member, and your
alternative is to fill in a form on the Oracle website and they will
analyze your submission and file a bug on your behalf at some point.
Hopefully.

This is not a ringing endorsement of OpenJDK as an *open* implementation
of Java, but it is what it is... I can't currently provide a public
ticket number but perhaps sometime in the future.

Closes: https://bugs.gentoo.org/916735
Signed-off-by: Eli Schwartz <eschwartz@gentoo.org>

dev-java/openjdk/openjdk-21.0.4_p7.ebuild

@@ -48,7 +48,8 @@ LICENSE="GPL-2-with-classpath-exception"
 SLOT="${MY_PV%%[.+]*}"
 KEYWORDS="~amd64 ~arm64 ~ppc64 ~x86"
 
-IUSE="alsa big-endian cups debug doc examples headless-awt javafx +jbootstrap lto selinux source +system-bootstrap systemtap"
+# lto temporarily disabled due to https://bugs.gentoo.org/916735
+IUSE="alsa big-endian cups debug doc examples headless-awt javafx +jbootstrap selinux source +system-bootstrap systemtap"
 
 REQUIRED_USE="
 	javafx? ( alsa !headless-awt )
@@ -225,7 +226,11 @@ src_configure() {
 
 	use riscv && myconf+=( --with-boot-jdk-jvmargs="-Djdk.lang.Process.launchMechanism=vfork" )
 
-	use lto && myconf+=( --with-jvm-features=link-time-opt )
+	# Werror=odr
+	# https://bugs.gentoo.org/916735
+	#
+	# Disable it for now.
+	#use lto && myconf+=( --with-jvm-features=link-time-opt )
 
 	if use javafx; then
 		local zip="${EPREFIX}/usr/$(get_libdir)/openjfx-${SLOT}/javafx-exports.zip"