curl...

CURLOPT_WRITEDATA and CURLOPT_READDATA

and proper select()ing have been made.

changed order of a few others to keep the a-z order

by the internal debugfunction callback

sized buffer that may be passed to a write callback

  trace dump get stored, with a full protocol dump that includes all received
  and transmitted data. This could be a very effective tool for debugging what
  goes wrong. This dump includes every byte the way it is sent to/received
  from the server. The dump is the plain-text version, so SSL transfers will
  still be readable.

for DATA_IN and DATA_OUT.

command line!

work properly with the multi interface when the user has provided the
fd_sets!

we need to point to user-provided fd_sets

from malloc()

before transfers, when doing multiple ones on the same handle.

even when the realloc() actually gets a new memory block

would reset the timeout for each incoming data, which would make veeery
slow responses be allowed to take even more time since the timeout would only
be reached if the time between two received data chunks was longer than the
set timeout value...

needed

used for "exported" globals.