Updated terminology in docs, comments and phrases to refer to C strings
as "null-terminated". Done to unify with how most other C oriented docs
refer of them and what users in general seem to prefer (based on a
single highly unscientific poll on twitter).
Reported-by: coinhubs on github
Fixes#5598Closes#5608
This feature is badly supported in Windows: as a replacement, a caller has
to use curl_mime_data_cb() with fread, fseek and possibly fclose
callbacks to process opened files.
The cli tool and documentation are updated accordingly.
The feature is however kept internally for form API compatibility, with
the known caveats it always had.
As a side effect, stdin size is not determined by the cli tool even if
possible and this results in a chunked transfer encoding. Test 173 is
updated accordingly.
