Previous commit was confused about the case we're handling: actually,
what the patch is dealing with is platforms that have optreset, *and*
have <getopt.h>, but the latter fails to declare the former. Because
we use a linking probe to set HAVE_INT_OPTRESET, we need to be sure we
have a declaration even if <getopt.h> doesn't think it exists.
Reportedly, some versions of mingw are like that, and it seems plausible
in general that older platforms might be that way. However, we'd
determined experimentally that just doing "extern int" conflicts with
the way Cygwin declares these variables, so explicitly exclude Cygwin.
Michael Paquier, tweaked by me to hopefully not break Cygwin
We used to have externs for getopt() and its API variables scattered
all over the place. Now that we find we're going to need to tweak the
variable declarations for Cygwin, it seems like a good idea to have
just one place to tweak.
In this commit, the variables are declared "#ifndef HAVE_GETOPT_H".
That may or may not work everywhere, but we'll soon find out.
Andres Freund
