[gnome-system-monitor] Fixed GCC8 compile warnings

[Robert Roth <robertroth src gnome org>]

commit 9977a1bf753e2cd0aa4801ef04d44d4ac3b06b12
Author: Robert Roth <robert roth off gmail com>
Date:   Mon Mar 1 10:22:32 2021 +0200

    Fixed GCC8 compile warnings

 src/load-graph.cpp | 5 +++--
 src/load-graph.h   | 4 ++--
 2 files changed, 5 insertions(+), 4 deletions(-)
---
diff --git a/src/load-graph.cpp b/src/load-graph.cpp
index 62292f38..b18bc61c 100644
--- a/src/load-graph.cpp
+++ b/src/load-graph.cpp
@@ -17,6 +17,7 @@
 #include "util.h"
 #include "legacy/gsm_color_button.h"
 
+gchar* format_duration(unsigned seconds);
 
 void LoadGraph::clear_background()
 {
@@ -901,7 +902,7 @@ LoadGraph::LoadGraph(guint type)
 
     switch (type) {
         case LOAD_GRAPH_CPU:
-            memset(&cpu, 0, sizeof cpu);
+            cpu = CPU {};
             n = GsmApplication::get()->config.num_cpus;
 
             for(guint i = 0; i < G_N_ELEMENTS(labels.cpu); ++i)
@@ -922,7 +923,7 @@ LoadGraph::LoadGraph(guint type)
             break;
 
         case LOAD_GRAPH_NET:
-            memset(&net, 0, sizeof net);
+            net = NET {};
             n = 2;
             net.max = 1;
             labels.net_in = make_tnum_label ();
diff --git a/src/load-graph.h b/src/load-graph.h
index 5ec71d5d..1a519ad2 100644
--- a/src/load-graph.h
+++ b/src/load-graph.h
@@ -87,7 +87,7 @@ struct LoadGraph
     Glib::RefPtr<Gio::Settings> font_settings;
 
     /* union { */
-    struct
+    struct CPU
     {
         guint now; /* 0 -> current, 1 -> last
                       now ^ 1 each time */
@@ -95,7 +95,7 @@ struct LoadGraph
         guint64 times[2][GLIBTOP_NCPU][N_CPU_STATES];
     } cpu;
 
-    struct
+    struct NET
     {
         guint64 last_in, last_out;
         guint64 time;