Update alffplay for newer ffmpeg and convert to C++

CMakeLists.txt

@@ -1514,29 +1514,29 @@ IF(ALSOFT_EXAMPLES)
         SET(FFVER_OK FALSE)
         IF(FFMPEG_FOUND)
             SET(FFVER_OK TRUE)
-            IF(AVFORMAT_VERSION VERSION_LESS "55.33.100")
-                MESSAGE(STATUS "libavformat is too old! (${AVFORMAT_VERSION}, wanted 55.33.100)")
+            IF(AVFORMAT_VERSION VERSION_LESS "57.56.101")
+                MESSAGE(STATUS "libavformat is too old! (${AVFORMAT_VERSION}, wanted 57.56.101)")
                 SET(FFVER_OK FALSE)
             ENDIF()
-            IF(AVCODEC_VERSION VERSION_LESS "55.52.102")
-                MESSAGE(STATUS "libavcodec is too old! (${AVCODEC_VERSION}, wanted 55.52.102)")
+            IF(AVCODEC_VERSION VERSION_LESS "57.64.101")
+                MESSAGE(STATUS "libavcodec is too old! (${AVCODEC_VERSION}, wanted 57.64.101)")
                 SET(FFVER_OK FALSE)
             ENDIF()
-            IF(AVUTIL_VERSION VERSION_LESS "52.66.100")
-                MESSAGE(STATUS "libavutil is too old! (${AVUTIL_VERSION}, wanted 52.66.100)")
+            IF(AVUTIL_VERSION VERSION_LESS "55.34.101")
+                MESSAGE(STATUS "libavutil is too old! (${AVUTIL_VERSION}, wanted 55.34.101)")
                 SET(FFVER_OK FALSE)
             ENDIF()
-            IF(SWSCALE_VERSION VERSION_LESS "2.5.102")
-                MESSAGE(STATUS "libswscale is too old! (${SWSCALE_VERSION}, wanted 2.5.102)")
+            IF(SWSCALE_VERSION VERSION_LESS "4.2.100")
+                MESSAGE(STATUS "libswscale is too old! (${SWSCALE_VERSION}, wanted 4.2.100)")
                 SET(FFVER_OK FALSE)
             ENDIF()
-            IF(SWRESAMPLE_VERSION VERSION_LESS "0.18.100")
-                MESSAGE(STATUS "libswresample is too old! (${SWRESAMPLE_VERSION}, wanted 0.18.100)")
+            IF(SWRESAMPLE_VERSION VERSION_LESS "2.3.100")
+                MESSAGE(STATUS "libswresample is too old! (${SWRESAMPLE_VERSION}, wanted 2.3.100)")
                 SET(FFVER_OK FALSE)
             ENDIF()
         ENDIF()
-        IF(FFVER_OK AND NOT MSVC)
-            ADD_EXECUTABLE(alffplay examples/alffplay.c ${COMMON_OBJS})
+        IF(FFVER_OK)
+            ADD_EXECUTABLE(alffplay examples/alffplay.cpp ${COMMON_OBJS})
             TARGET_LINK_LIBRARIES(alffplay ${SDL2_LIBRARY} OpenAL ${FFMPEG_LIBRARIES})
             SET_PROPERTY(TARGET alffplay APPEND PROPERTY COMPILE_FLAGS ${EXTRA_CFLAGS})
             SET_PROPERTY(TARGET alffplay APPEND PROPERTY