Avoid unnecessary const violation.

diff --git a/src/supported.c b/src/supported.c
index b8cb37a5291113f30ba6289fd57632903f0fbce0..f34562e3fab339df8d3454c5d0a47abb16455c92 100644 (file)
--- a/src/supported.c
+++ b/src/supported.c
@@ -116,7 +116,7 @@ change_isupport(const char *name, const char *(*func)(const void *), const void
 {
        rb_dlink_node *ptr;
        struct isupportitem *item;
-       void *oldvalue;
+       const void *oldvalue;
 
        RB_DLINK_FOREACH(ptr, isupportlist.head)
        {