typecheck-gcc: add support for CURLINFO_OFF_T

[MarcelRaad]

typecheck-gcc expected curl_socket_t instead of curl_off_t arguments
for CURLINFO_OFF_T. Detected by test1521, unfortunately only when run
locally.

[MarcelRaad]

The problem is that the GCC-release combination of the travis build runs on OSX. The default GCC is 4.2.1 there, which is not supported by typecheck-gcc.h. Maybe it could be changed to use gcc-4.8 instead, or the Linux GCC build switched to release mode and the OSX GCC build to debug mode?

[bagder]

Maybe it could be changed to use gcc-4.8 instead

I think it is possible. My googling found this example of someone doing it.

or the Linux GCC build switched to release mode and the OSX GCC build to debug mode?

They could indeed, or we could also just add a build if we need to! It's just to make a PR with a .travis.yml update to try it out!

[MarcelRaad]

It's just to make a PR with a .travis.yml update to try it out!

Ah, so the changed .travis.yml is immediately used for the PR? That's nice!

[coveralls]

Coverage decreased (-0.008%) to 73.801% when pulling 1a0602b36f61a570094fa70b7b5d64a3b3f1c836 on MarcelRaad:typecheck_off_t_info into b778ae4 on curl:master.

[bagder]

Yes, exactly!

[coveralls]

Coverage increased (+0.01%) to 73.793% when pulling cab32a4e5efde385ce0da32f8692162d426a10c5 on MarcelRaad:typecheck_off_t_info into 0feb762 on curl:master.

[coveralls]

Coverage increased (+0.01%) to 73.801% when pulling 01d9670 on MarcelRaad:typecheck_off_t_info into 651e04c on curl:master.

[MarcelRaad]

Thanks!