dynbuf: introduce internal generic dynamic buffer functions

A common set of functions instead of many separate implementations for
creating buffers that can grow when appending data to them. Existing
functionality has been ported over.

In my early basic testing, the total number of allocations seem at
roughly the same amount as before, possibly a few less.

See docs/DYNBUF.md for a description of the API.

Closes #5300

1 files changed, 1 insertions, 1 deletions

diff --git a/lib/multi.c b/lib/multi.c
index b77a9a0ee..75b0357c3 100644
--- a/lib/multi.c
+++ b/lib/multi.c
@@ -616,7 +616,7 @@ static CURLcode multi_done(struct Curl_easy *data,
   /* if the transfer was completed in a paused state there can be buffered
      data left to free */
   for(i = 0; i < data->state.tempcount; i++) {
-    free(data->state.tempwrite[i].buf);
+    Curl_dyn_free(&data->state.tempwrite[i].b);
   }
   data->state.tempcount = 0;