--- cups/transcode.c.orig
+++ cups/transcode.c
@@ -164,7 +164,7 @@ cupsCharsetToUTF8(
     srclen       = strlen(src);
     outBytesLeft = (size_t)maxout - 1;
 
-    iconv(map_to_utf8, (char **)&src, &srclen, &altdestptr, &outBytesLeft);
+    iconv(map_to_utf8, (const char **)&src, &srclen, &altdestptr, &outBytesLeft);
     *altdestptr = '\0';
 
     _cupsMutexUnlock(&map_mutex);
@@ -293,7 +293,7 @@ cupsUTF8ToCharset(
     srclen       = strlen((char *)src);
     outBytesLeft = (size_t)maxout - 1;
 
-    iconv(map_from_utf8, &altsrc, &srclen, &destptr, &outBytesLeft);
+    iconv(map_from_utf8, (const char **)&altsrc, &srclen, &destptr, &outBytesLeft);
     *destptr = '\0';
 
     _cupsMutexUnlock(&map_mutex);