2008-03-21 Marcus Brinkmann <marcus@g10code.de>

• assuan-defs.h (_assuan_usleep): New prototype.
• assuan-io.c (_assuan_usleep): New function.
• assuan-io-pth.c (_assuan_usleep): New function.
• mkerrors: Do not incude <windows.h>, but assuan-defs.h.

(_assuan_error_is_eagain): Call _assuan_usleep.