Fix build of VLC with Qt 5.15. Otherwise it fails like this:

------
In file included from gui/qt/util/timetooltip.moc.cpp:10:0:
gui/qt/util/timetooltip.hpp:49:18: error: field ‘mPainterPath’ has incomplete type ‘QPainterPath’
     QPainterPath mPainterPath;
                  ^~~~~~~~~~~~
In file included from /gnu/store/jsxxnsdvij5mrrv6c0kj0261k0f44xlz-qtbase-5.15.2/include/qt5/QtGui/qbrush.h:49:0,
                 from /gnu/store/jsxxnsdvij5mrrv6c0kj0261k0f44xlz-qtbase-5.15.2/include/qt5/QtGui/qpalette.h:46,
                 from /gnu/store/jsxxnsdvij5mrrv6c0kj0261k0f44xlz-qtbase-5.15.2/include/qt5/QtWidgets/qwidget.h:48,
                 from /gnu/store/jsxxnsdvij5mrrv6c0kj0261k0f44xlz-qtbase-5.15.2/include/qt5/QtWidgets/QWidget:1,
                 from gui/qt/util/timetooltip.hpp:27,
                 from gui/qt/util/timetooltip.moc.cpp:10:
/gnu/store/jsxxnsdvij5mrrv6c0kj0261k0f44xlz-qtbase-5.15.2/include/qt5/QtGui/qmatrix.h:54:7: note: forward declaration of ‘class QPainterPath’
 class QPainterPath;
       ^~~~~~~~~~~~
make[4]: *** [Makefile:25852: gui/qt/util/libqt_plugin_la-timetooltip.moc.lo] Error 1
------

diff --git a/modules/gui/qt/components/playlist/views.cpp b/modules/gui/qt/components/playlist/views.cpp
index 24db9d9..73c1779 100644
--- a/modules/gui/qt/components/playlist/views.cpp
+++ b/modules/gui/qt/components/playlist/views.cpp
@@ -27,6 +27,7 @@
 #include "input_manager.hpp"                      /* THEMIM */
 
 #include <QPainter>
+#include <QPainterPath>
 #include <QRect>
 #include <QStyleOptionViewItem>
 #include <QFontMetrics>
diff --git a/modules/gui/qt/dialogs/plugins.cpp b/modules/gui/qt/dialogs/plugins.cpp
index d233382..69728eb 100644
--- a/modules/gui/qt/dialogs/plugins.cpp
+++ b/modules/gui/qt/dialogs/plugins.cpp
@@ -53,6 +53,7 @@
 #include <QListView>
 #include <QListWidget>
 #include <QPainter>
+#include <QPainterPath>
 #include <QStyleOptionViewItem>
 #include <QKeyEvent>
 #include <QPushButton>
diff --git a/modules/gui/qt/util/timetooltip.hpp b/modules/gui/qt/util/timetooltip.hpp
index 6a1329e..9f50b18 100644
--- a/modules/gui/qt/util/timetooltip.hpp
+++ b/modules/gui/qt/util/timetooltip.hpp
@@ -25,6 +25,7 @@
 #include "qt.hpp"
 
 #include <QWidget>
+#include <QPainterPath>
 
 class TimeTooltip : public QWidget
 {