The SUNWspro compiler does not define __sun__ (like GCC does). A check of
this macro was recently added to detect compilation on SunOS and to modify
the handling of the NO_ICONV and _XOPEN_SOURCE feature macros.
Signed-off-by: Brandon Casey <drafnel@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>