Use safer xine_get_current_frame_s

xine_get_current_frame was deprecated back in 2019 because it is
"unsafe by design"[0].  The '_s' version was introduced in xine-lib
1.1.11, which was released in 2008, so there are no version checks.

[0]:
c1a154c1a8

Signed-off-by: mio <stigma@disroot.org>

kaffeine/src/player-parts/xine-part/kxinewidget.cpp

@@ -3834,17 +3834,18 @@ void KXineWidget::getScreenshot(uchar*& rgb32BitData, int& videoWidth, int& vide
 	int        width, height, ratio, format;
 	// double     desired_ratio, image_ratio;
 
-	if (!xine_get_current_frame(m_xineStream, &width, &height, &ratio, &format, NULL))
+	if (!xine_get_current_frame_s(m_xineStream, &width, &height, &ratio, &format, nullptr, nullptr))
 		return;
 
-	yuv = new uint8_t[((width+8) * (height+1) * 2)];
+	int yuv_size = ((width + 8) * (height + 1)) * 2;
+	yuv = new uint8_t[yuv_size];
 	if (yuv == NULL)
 	{
 		errorOut("Not enough memory to make screenshot!");
 		return;
 	}
 
-	xine_get_current_frame(m_xineStream, &width, &height, &ratio, &format, yuv);
+	xine_get_current_frame_s(m_xineStream, &width, &height, &ratio, &format, yuv, &yuv_size);
 
 	videoWidth = width;
 	videoHeight = height;