XIMEA cam support: allow on OS X too

CMakeLists.txt

@@ -153,7 +153,7 @@ OCV_OPTION(WITH_V4L            "Include Video 4 Linux support"               ON
 OCV_OPTION(WITH_LIBV4L         "Use libv4l for Video 4 Linux support"        ON   IF (UNIX AND NOT ANDROID) )
 OCV_OPTION(WITH_DSHOW          "Build VideoIO with DirectShow support"       ON   IF (WIN32 AND NOT ARM) )
 OCV_OPTION(WITH_MSMF           "Build VideoIO with Media Foundation support" OFF  IF WIN32 )
-OCV_OPTION(WITH_XIMEA          "Include XIMEA cameras support"               OFF  IF (NOT ANDROID AND NOT APPLE) )
+OCV_OPTION(WITH_XIMEA          "Include XIMEA cameras support"               OFF  IF (NOT ANDROID) )
 OCV_OPTION(WITH_XINE           "Include Xine support (GPL)"                  OFF  IF (UNIX AND NOT APPLE AND NOT ANDROID) )
 OCV_OPTION(WITH_CLP            "Include Clp support (EPL)"                   OFF)
 OCV_OPTION(WITH_OPENCL         "Include OpenCL Runtime support"              ON   IF (NOT IOS) )

cmake/OpenCVFindXimea.cmake

@@ -31,6 +31,12 @@ if(WIN32)
   else()
     set(XIMEA_FOUND 0)
   endif()
+elseif(APPLE)
+  if(EXISTS /Library/Frameworks/m3api.framework)
+    set(XIMEA_FOUND 1)
+  else()
+    set(XIMEA_FOUND 0)
+  endif()
 else()
   if(EXISTS /opt/XIMEA)
     set(XIMEA_FOUND 1)

modules/videoio/CMakeLists.txt

@@ -102,6 +102,8 @@ if(HAVE_XIMEA)
   endif()
   if(WIN32 AND X86_64)
     list(APPEND VIDEOIO_LIBRARIES m3apiX64)
+  elseif(APPLE)
+    list(APPEND VIDEOIO_LIBRARIES "-framework m3api")
   else()
     list(APPEND VIDEOIO_LIBRARIES m3api)
   endif()