#413 WIN32: MSVC: gettimeofday() is unsupported.

[Carlo Bramini]

Unfortunately, src/screenshot.c cannot be compiled on MSVC because:

• sys/time.h is unsupported.
• gettimeofday() is also unsupported.
  Both conditions are already tested by configure script, so I just needed to add some #ifdef...#endif.
  However, it seems to me that a replacement doesn't exists, so I did the patch but I left it open for additional development.

[gpz]

While this fix makes it build.... it results in non working behaviour (screenshots will overwrite each other). Perhaps instead of the current time, a simple counter can be added to prevent this?

[gpz]

slightly modified patch applied in r45878, thanks!