lavfi/histogram: switch to an AVOptions-based system.

doc/filters.texi

@@ -3474,7 +3474,7 @@ Compute and draw a color distribution histogram for the input video.
 The computed histogram is a representation of distribution of color components
 in an image.
 
-The filter accepts the following named parameters:
+The filter accepts the following options:
 
 @table @option
 @item mode

libavfilter/avfilter.c

@@ -680,6 +680,7 @@ int avfilter_init_filter(AVFilterContext *filter, const char *args, void *opaque
         !strcmp(filter->filter->name,  "geq"       ) ||
         !strcmp(filter->filter->name, "gradfun"    ) ||
         !strcmp(filter->filter->name, "histeq"     ) ||
+        !strcmp(filter->filter->name, "histogram"  ) ||
         !strcmp(filter->filter->name, "hqdn3d"     ) ||
         !strcmp(filter->filter->name, "ocv"        ) ||
         !strcmp(filter->filter->name, "life"       ) ||

libavfilter/vf_histogram.c

@@ -311,8 +311,6 @@ static const AVFilterPad outputs[] = {
     { NULL }
 };
 
-static const char *const shorthand[] = { NULL };
-
 AVFilter avfilter_vf_histogram = {
     .name          = "histogram",
     .description   = NULL_IF_CONFIG_SMALL("Compute and draw a histogram."),
@@ -321,5 +319,4 @@ AVFilter avfilter_vf_histogram = {
     .inputs        = inputs,
     .outputs       = outputs,
     .priv_class    = &histogram_class,
-    .shorthand     = shorthand,
 };