unbreak multimedia/qtav with upcoming Qt updates

Here is a patch to fix QtAV with Qt 5.9.8 and upcoming updates.

OK? Objections?

RS

Index: Makefile
===================================================================
RCS file: /cvs/ports/multimedia/qtav/Makefile,v
retrieving revision 1.4
diff -u -p -u -p -r1.4 Makefile
--- Makefile 15 Jul 2019 21:50:18 -0000 1.4
+++ Makefile 1 Nov 2019 06:34:56 -0000
@@ -5,7 +5,7 @@ COMMENT = FFmpeg-based Qt multimedia fra
GH_ACCOUNT = wang-bin
GH_PROJECT = QtAV
GH_TAGNAME = v1.12.0
-REVISION = 0
+REVISION = 1

PKGNAME = ${DISTNAME:L}

@@ -38,6 +38,8 @@ LIB_DEPENDS = audio/openal \
x11/qt5/qtdeclarative

MODQMAKE_ENV += TRUEPREFIX=${TRUEPREFIX}
+
+SUBST_VARS = QT5_VERSION

# The examples are GLPv3 licencensed and have too generic names, like 'Player',
# so don't install them.
Index: pkg/PLIST
===================================================================
RCS file: /cvs/ports/multimedia/qtav/pkg/PLIST,v
retrieving revision 1.1.1.1
diff -u -p -u -p -r1.1.1.1 PLIST
--- pkg/PLIST 2 May 2019 12:26:15 -0000 1.1.1.1
+++ pkg/PLIST 1 Nov 2019 06:34:56 -0000
@@ -1,27 +1,27 @@
@comment $OpenBSD: PLIST,v 1.1.1.1 2019/05/02 12:26:15 rsadowski Exp $
include/X11/qt5/QtAV/
-include/X11/qt5/QtAV/5.9.7/
-include/X11/qt5/QtAV/5.9.7/QtAV/
-include/X11/qt5/QtAV/5.9.7/QtAV/private/
-include/X11/qt5/QtAV/5.9.7/QtAV/private/AVCompat.h
-include/X11/qt5/QtAV/5.9.7/QtAV/private/AVDecoder_p.h
-include/X11/qt5/QtAV/5.9.7/QtAV/private/AVEncoder_p.h
-include/X11/qt5/QtAV/5.9.7/QtAV/private/AVOutput_p.h
-include/X11/qt5/QtAV/5.9.7/QtAV/private/AudioOutputBackend.h
-include/X11/qt5/QtAV/5.9.7/QtAV/private/AudioResampler_p.h
-include/X11/qt5/QtAV/5.9.7/QtAV/private/Filter_p.h
-include/X11/qt5/QtAV/5.9.7/QtAV/private/Frame_p.h
-include/X11/qt5/QtAV/5.9.7/QtAV/private/MediaIO_p.h
-include/X11/qt5/QtAV/5.9.7/QtAV/private/OpenGLRendererBase_p.h
-include/X11/qt5/QtAV/5.9.7/QtAV/private/PlayerSubtitle.h
-include/X11/qt5/QtAV/5.9.7/QtAV/private/QPainterRenderer_p.h
-include/X11/qt5/QtAV/5.9.7/QtAV/private/SubtitleProcessor.h
-include/X11/qt5/QtAV/5.9.7/QtAV/private/VideoRenderer_p.h
-include/X11/qt5/QtAV/5.9.7/QtAV/private/VideoShader_p.h
-include/X11/qt5/QtAV/5.9.7/QtAV/private/factory.h
-include/X11/qt5/QtAV/5.9.7/QtAV/private/mkid.h
-include/X11/qt5/QtAV/5.9.7/QtAV/private/prepost.h
-include/X11/qt5/QtAV/5.9.7/QtAV/private/singleton.h
+include/X11/qt5/QtAV/${QT5_VERSION}/
+include/X11/qt5/QtAV/${QT5_VERSION}/QtAV/
+include/X11/qt5/QtAV/${QT5_VERSION}/QtAV/private/
+include/X11/qt5/QtAV/${QT5_VERSION}/QtAV/private/AVCompat.h
+include/X11/qt5/QtAV/${QT5_VERSION}/QtAV/private/AVDecoder_p.h
+include/X11/qt5/QtAV/${QT5_VERSION}/QtAV/private/AVEncoder_p.h
+include/X11/qt5/QtAV/${QT5_VERSION}/QtAV/private/AVOutput_p.h
+include/X11/qt5/QtAV/${QT5_VERSION}/QtAV/private/AudioOutputBackend.h
+include/X11/qt5/QtAV/${QT5_VERSION}/QtAV/private/AudioResampler_p.h
+include/X11/qt5/QtAV/${QT5_VERSION}/QtAV/private/Filter_p.h
+include/X11/qt5/QtAV/${QT5_VERSION}/QtAV/private/Frame_p.h
+include/X11/qt5/QtAV/${QT5_VERSION}/QtAV/private/MediaIO_p.h
+include/X11/qt5/QtAV/${QT5_VERSION}/QtAV/private/OpenGLRendererBase_p.h
+include/X11/qt5/QtAV/${QT5_VERSION}/QtAV/private/PlayerSubtitle.h
+include/X11/qt5/QtAV/${QT5_VERSION}/QtAV/private/QPainterRenderer_p.h
+include/X11/qt5/QtAV/${QT5_VERSION}/QtAV/private/SubtitleProcessor.h
+include/X11/qt5/QtAV/${QT5_VERSION}/QtAV/private/VideoRenderer_p.h
+include/X11/qt5/QtAV/${QT5_VERSION}/QtAV/private/VideoShader_p.h
+include/X11/qt5/QtAV/${QT5_VERSION}/QtAV/private/factory.h
+include/X11/qt5/QtAV/${QT5_VERSION}/QtAV/private/mkid.h
+include/X11/qt5/QtAV/${QT5_VERSION}/QtAV/private/prepost.h
+include/X11/qt5/QtAV/${QT5_VERSION}/QtAV/private/singleton.h
include/X11/qt5/QtAV/AVClock.h
include/X11/qt5/QtAV/AVDecoder.h
include/X11/qt5/QtAV/AVDemuxer.h