diff --git a/net-libs/signon-oauth2/files/signon-oauth2-0.21-unused-dependency.patch b/net-libs/signon-oauth2/files/signon-oauth2-0.21-unused-dependency.patch
new file mode 100644
index 0000000000000..3e6656dd272c6
--- /dev/null
+++ b/net-libs/signon-oauth2/files/signon-oauth2-0.21-unused-dependency.patch
@@ -0,0 +1,16 @@
+Qt5XmlPatterns is not actually used, but build will fail if it's missing.
+
+Gentoo-bug: 564316
+
+--- src/src.pro
++++ src/src.pro
+@@ -4,8 +4,7 @@
+ TARGET = oauth2plugin
+ DESTDIR = lib/signon
+ QT += core \
+-    network \
+-    xmlpatterns
++    network
+ QT -= gui
+ CONFIG += plugin \
+     build_all \
diff --git a/net-libs/signon-oauth2/signon-oauth2-0.21.ebuild b/net-libs/signon-oauth2/signon-oauth2-0.21.ebuild
index 2c5b49bc870f7..2bbabd6efc1b5 100644
--- a/net-libs/signon-oauth2/signon-oauth2-0.21.ebuild
+++ b/net-libs/signon-oauth2/signon-oauth2-0.21.ebuild
@@ -4,7 +4,7 @@
 
 EAPI=5
 
-inherit qmake-utils
+inherit eutils qmake-utils
 
 DESCRIPTION="OAuth2 plugin for Signon daemon"
 HOMEPAGE="https://01.org/gsso/"
@@ -30,6 +30,8 @@ src_prepare() {
 	else
 		sed -i -e '/^INSTALLS.*/,+1d' tests/tests.pro || die "couldn't remove tests from install target"
 	fi
+
+	epatch "${FILESDIR}/${P}-unused-dependency.patch"
 }
 
 src_configure() {