Don't call static methods through an instance. NFC.

Found by clang-tidy.

src/exportvector.cpp

@@ -325,7 +325,7 @@ public:
 
     void assignEntityDefaults(DRW_Entity *entity, hStyle hs) {
         Style *s = Style::Get(hs);
-        RgbaColor color = s->Color(hs, /*forExport=*/true);
+        RgbaColor color = Style::Color(hs, /*forExport=*/true);
         entity->color24 = color.ToPackedIntBGRA();
         entity->color = findDxfColor(color);
         entity->layer = s->DescriptionString();

src/platform/guigtk.cpp

@@ -1471,11 +1471,11 @@ void InitGui(int argc, char **argv) {
 }
 
 void RunGui() {
-    gtkMain->run();
+    Gtk::Main::run();
 }
 
 void ExitGui() {
-    gtkMain->quit();
+    Gtk::Main::quit();
 }
 
 void ClearGui() {