configure: silence pkg-config's check for curses

Signed-off-by: Vadim Evard <v.e.evard@gmail.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
diff --git a/configure b/configure
index 4ebb60d..6211db9 100755
--- a/configure
+++ b/configure
@@ -2039,7 +2039,7 @@
 if test "$mingw32" = "yes" ; then
     curses_list="-lpdcurses"
 else
-    curses_list="-lncurses:-lcurses:$($pkg_config --libs ncurses)"
+    curses_list="-lncurses:-lcurses:$($pkg_config --libs ncurses 2>/dev/null)"
 fi
 
 if test "$curses" != "no" ; then