x11-plugins/gkrellmss: fix build with gcc-10

* Thanks to Jack Ostroff <ostroffjh@users.sourceforge.net> for
  submitting the original patch

Closes: https://bugs.gentoo.org/708804
Package-Manager: Portage-3.0.9, Repoman-3.0.1
Signed-off-by: Jakov Smolic <jakov.smolic@sartura.hr>
Signed-off-by: David Seifert <soap@gentoo.org>

x11-plugins/gkrellmss/files/gkrellmss-2.6-fno-common.patch

@@ -0,0 +1,12 @@
+--- a/src/gkrellmss.h
++++ b/src/gkrellmss.h
+@@ -212,7 +212,7 @@
+ #define	DRAW_GRID	1
+ 
+ 
+-SoundMonitor	*gkrellmss;
++extern SoundMonitor *gkrellmss;
+ 
+ 
+ void		gkrellmss_add_sound_sources(void);
+

x11-plugins/gkrellmss/gkrellmss-2.6-r4.ebuild

@@ -1,4 +1,4 @@
-# Copyright 1999-2018 Gentoo Foundation
+# Copyright 1999-2020 Gentoo Authors
 # Distributed under the terms of the GNU General Public License v2
 
 EAPI=6
@@ -20,7 +20,10 @@ RDEPEND="
 	sci-libs/fftw:3.0="
 DEPEND="${RDEPEND}"
 
-PATCHES=( "${FILESDIR}"/${P}-Respect-LDFLAGS.patch )
+PATCHES=(
+	"${FILESDIR}"/${P}-Respect-LDFLAGS.patch
+	"${FILESDIR}"/${P}-fno-common.patch
+)
 
 PLUGIN_SO=( src/gkrellmss$(get_modname) )
 PLUGIN_DOCS=( Themes )