Add #defines needed by OpenSolaris, fix breakage by the #defines

We need to define _XOPEN_SOURCE and __EXTENSIONS__ macros in order to get
CMSG_ and TIOCWIN macros defined. But then _POSIX_C_SOURCE gets defined, which
is (incorrectly) used as an indicator for existence of posix_memalign() in osdep.c.

Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
diff --git a/configure b/configure
index 646da75..1160cf6 100755
--- a/configure
+++ b/configure
@@ -326,6 +326,10 @@
     audio_drv_list="oss"
   fi
   audio_possible_drivers="oss sdl"
+# needed for CMSG_ macros in sys/socket.h
+  QEMU_CFLAGS="-D_XOPEN_SOURCE=600 $QEMU_CFLAGS"
+# needed for TIOCWIN* defines in termios.h
+  QEMU_CFLAGS="-D__EXTENSIONS__ $QEMU_CFLAGS"
   QEMU_CFLAGS="-std=gnu99 $QEMU_CFLAGS"
   LIBS="-lsocket -lnsl -lresolv $LIBS"
 ;;