configure: Add HAX support in NetBSD

The NetBSD support in Intel HAXM has beem merged upstream and is functional.

Signed-off-by: Kamil Rytarowski <n54@gmx.com>
Message-Id: <20190207233704.29978-1-n54@gmx.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
diff --git a/configure b/configure
index c8fc164..649ef1b 100755
--- a/configure
+++ b/configure
@@ -817,6 +817,7 @@
 ;;
 NetBSD)
   bsd="yes"
+  hax="yes"
   make="${MAKE-gmake}"
   audio_drv_list="oss try-sdl"
   audio_possible_drivers="oss sdl"