This function must be the first function to call, and it returns a CURL easy
handle that you must use as input to other easy-functions. curl_easy_init
initializes curl and this call MUST have a corresponding call to
curl_easy_cleanup(3) when the operation is complete.
If you did not already call curl_global_init(3),
curl_easy_init(3) does it automatically.
This may be lethal in multi-threaded cases, since curl_global_init(3) is
not thread-safe, and it may result in resource problems because there is
no corresponding cleanup.
You are strongly advised to not allow this automatic behaviour, by
calling curl_global_init(3) yourself properly.
See the description in libcurl(3) of global environment
requirements for details of how to use this function.