diff --git a/sci-electronics/xoscope/xoscope-2.3.ebuild b/sci-electronics/xoscope/xoscope-2.3.ebuild
index 69434a3f9cfce..59831c2b3e22a 100644
--- a/sci-electronics/xoscope/xoscope-2.3.ebuild
+++ b/sci-electronics/xoscope/xoscope-2.3.ebuild
@@ -1,9 +1,9 @@
-# Copyright 1999-2023 Gentoo Authors
+# Copyright 1999-2024 Gentoo Authors
 # Distributed under the terms of the GNU General Public License v2
 
 EAPI=8
 
-inherit autotools linux-info
+inherit autotools flag-o-matic linux-info
 
 DESCRIPTION="Soundcard Oscilloscope for X"
 HOMEPAGE="http://xoscope.sourceforge.net"
@@ -32,3 +32,12 @@ src_prepare() {
 	default
 	eautoreconf
 }
+
+src_compile() {
+	# -Werror=lto-type-mismatch
+	# https://bugs.gentoo.org/878065
+	# Upstream is a) sourceforge, b) inactive for 3 years. Bug not reported.
+	filter-lto
+
+	default
+}