The integer literal 3123123123 doesn't fit into a 32-bit signed
integer, so GCC with 32-bit long warns in C90 mode:
this decimal constant is unsigned only in ISO C90 [enabled by default]
Fix this by using ULONG_MAX, which should fit in any curl_off_t and has
the correct suffix to not issue any warnings.
Also adds the missing CURLOPT_REQUEST_TARGET from commit
9b167fd090.
Closes https://github.com/curl/curl/pull/1611
mk-lib1521.pl generates a test program (lib1521.c) that calls
curl_easy_setopt() for every known option with a few typical values to
make sure they work (ignoring the return codes).
Some small changes were necessary to avoid asserts and NULL accesses
when doing this.
The perl script needs to be manually rerun when we add new options.
Closes#1543
Daniel Stenberg