Create the Video library even without gstreamer

src/VideoStreaming/CMakeLists.txt

+set(EXTRA_LIBRARIES)
+
 if (GST_FOUND)
-    include_directories(
-        gstqtvideosink/utils/
-        )
+	include_directories(
+		gstqtvideosink/utils/
+	)
 
-    set(EXTRA_SRC
-        gstqtvideosink/delegates/basedelegate.cpp
-        gstqtvideosink/delegates/qtquick2videosinkdelegate.cpp
-        gstqtvideosink/delegates/qtvideosinkdelegate.cpp
-        gstqtvideosink/delegates/qwidgetvideosinkdelegate.cpp
-        gstqtvideosink/gstqtglvideosink.cpp
-        gstqtvideosink/gstqtglvideosinkbase.cpp
-        gstqtvideosink/gstqtquick2videosink.cpp
-        gstqtvideosink/gstqtvideosink.cpp
-        gstqtvideosink/gstqtvideosinkbase.cpp
-        gstqtvideosink/gstqtvideosinkplugin.cpp
-        gstqtvideosink/gstqwidgetvideosink.cpp
-        gstqtvideosink/gstqtvideosinkmarshal.c
-        gstqtvideosink/painters/genericsurfacepainter.cpp
-        gstqtvideosink/painters/openglsurfacepainter.cpp
-        gstqtvideosink/painters/videomaterial.cpp
-        gstqtvideosink/painters/videonode.cpp
-        gstqtvideosink/utils/bufferformat.cpp
-        gstqtvideosink/utils/utils.cpp
-    )
+	set(EXTRA_SRC
+		gstqtvideosink/delegates/basedelegate.cpp
+		gstqtvideosink/delegates/qtquick2videosinkdelegate.cpp
+		gstqtvideosink/delegates/qtvideosinkdelegate.cpp
+		gstqtvideosink/delegates/qwidgetvideosinkdelegate.cpp
+		gstqtvideosink/gstqtglvideosink.cpp
+		gstqtvideosink/gstqtglvideosinkbase.cpp
+		gstqtvideosink/gstqtquick2videosink.cpp
+		gstqtvideosink/gstqtvideosink.cpp
+		gstqtvideosink/gstqtvideosinkbase.cpp
+		gstqtvideosink/gstqtvideosinkplugin.cpp
+		gstqtvideosink/gstqwidgetvideosink.cpp
+		gstqtvideosink/gstqtvideosinkmarshal.c
+		gstqtvideosink/painters/genericsurfacepainter.cpp
+		gstqtvideosink/painters/openglsurfacepainter.cpp
+		gstqtvideosink/painters/videomaterial.cpp
+		gstqtvideosink/painters/videonode.cpp
+		gstqtvideosink/utils/bufferformat.cpp
+		gstqtvideosink/utils/utils.cpp
+	)
+	set(EXTRA_LIBRARIES ${GST_LIBRARIES})
+endif()
 
-    add_library(VideoStreaming
-        VideoItem.cc
-        VideoReceiver.cc
-        VideoStreaming.cc
-        VideoSurface.cc
-        SubtitleWriter.cc
-        ${EXTRA_SRC}
-    )
+add_library(VideoStreaming
+	VideoItem.cc
+	VideoReceiver.cc
+	VideoStreaming.cc
+	VideoSurface.cc
+	SubtitleWriter.cc
+	${EXTRA_SRC}
+)
 
-    target_link_libraries(VideoStreaming
-        PUBLIC
-            qgc
-            Qt5::Multimedia
-            Qt5::OpenGL
-            ${GST_LIBRARIES}
-    )
+target_link_libraries(VideoStreaming
+	PUBLIC
+		qgc
+		Qt5::Multimedia
+		Qt5::OpenGL
+		${EXTRA_LIBRARIES}
+)
 
-    target_include_directories(VideoStreaming INTERFACE ${CMAKE_CURRENT_SOURCE_DIR})
-endif()
+target_include_directories(VideoStreaming INTERFACE ${CMAKE_CURRENT_SOURCE_DIR})