OpenCV 2 compat

OpenCV 2 (at least in CentOS 7) has the imgproc.hpp header in
(opencv2/)imgproc/ subdirectory. Instead of tweaking the location,
include opencv.hpp directly if available (as it was before 2db2a73803).

configure.ac

@@ -1319,6 +1319,9 @@ if test "$opencv_req" != no; then
 fi
 
 if test "$opencv" = yes; then
+        AC_LANG_PUSH(C++)
+        AC_CHECK_HEADERS([opencv2/opencv.hpp])
+        AC_LANG_POP(C++)
         # opencv_imgproc is commonly needed so make the check here
         SAVED_LIBS=$LIBS
         LIBS="$LIBS $OPENCV_LIBS"

src/capture_filter/resize_utils.cpp

@@ -6,7 +6,7 @@
  */
 /*
  * Copyright (c) 2014      Fundació i2CAT, Internet I Innovació Digital a Catalunya
- * Copyright (c) 2015-2021 CESNET, z. s. p. o.
+ * Copyright (c) 2015-2023 CESNET, z. s. p. o.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, is permitted provided that the following conditions
@@ -54,8 +54,12 @@
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wcast-align"
 #pragma GCC diagnostic ignored "-Wcast-qual"
+#ifdef HAVE_OPENCV2_OPENCV_HPP
+#include <opencv2/opencv.hpp>
+#else
 #include <opencv2/imgproc.hpp>
 #include <opencv2/imgproc/types_c.h>
+#endif
 #pragma GCC diagnostic pop
 
 #include "capture_filter/resize_utils.h"

src/video_display/conference.cpp

@@ -4,7 +4,7 @@
  * @author Martin Piatka    <piatka@cesnet.cz>
  */
 /*
- * Copyright (c) 2014-2022 CESNET, z. s. p. o.
+ * Copyright (c) 2014-2023 CESNET, z. s. p. o.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -64,8 +64,12 @@
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wcast-align"
 #pragma GCC diagnostic ignored "-Wcast-qual"
+#ifdef HAVE_OPENCV2_OPENCV_HPP
+#include <opencv2/opencv.hpp>
+#else
 #include <opencv2/core/mat.hpp>
 #include <opencv2/imgproc.hpp>
+#endif
 #pragma GCC diagnostic pop
 
 #ifdef __SSSE3__