avcodec/options: add missing FF_API_COPY_CONTEXT checks

Signed-off-by: James Almer <jamrial@gmail.com>

libavcodec/options.c

@@ -327,6 +327,7 @@ static const AVOption frame_options[]={
 {NULL},
 };
 
+#if FF_API_COPY_CONTEXT
 static const AVClass av_frame_class = {
     .class_name              = "AVFrame",
     .item_name               = NULL,
@@ -338,6 +339,7 @@ const AVClass *avcodec_get_frame_class(void)
 {
     return &av_frame_class;
 }
+#endif
 
 #define SROFFSET(x) offsetof(AVSubtitleRect,x)
 
@@ -352,6 +354,7 @@ static const AVOption subtitle_rect_options[]={
 {NULL},
 };
 
+#if FF_API_COPY_CONTEXT
 static const AVClass av_subtitle_rect_class = {
     .class_name             = "AVSubtitleRect",
     .item_name              = NULL,
@@ -363,3 +366,4 @@ const AVClass *avcodec_get_subtitle_rect_class(void)
 {
     return &av_subtitle_rect_class;
 }
+#endif