define _OPENBSD_SOURCE for reallocarray on NetBSD

Report by and debugged with Hisashi T Fujinaka, dtucker nailed
the problem (lack of prototype causing return type confusion).

diff --git a/configure.ac b/configure.ac
index e64386f063378627ab3e48d74475e3a83c0df785..373d21b346c27db817c2302cf64a89cbbda986ad 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -839,6 +839,7 @@ mips-sony-bsd|mips-sony-newsos4)
        if test "x$withval" != "xno" ; then
                need_dash_r=1
        fi
+       CPPFLAGS="$CPPFLAGS -D_OPENBSD_SOURCE"
        AC_DEFINE([SSH_TUN_FREEBSD], [1], [Open tunnel devices the FreeBSD way])
        AC_CHECK_HEADER([net/if_tap.h], ,
            AC_DEFINE([SSH_TUN_NO_L2], [1], [No layer 2 tunnel support]))