fix automagic dependency on vcdinfo

when --enable-libcdio was passed to configure, vcdinfo was searched and
linked against if found (only do that when vcdinfo wasn't disabled)
Signed-off-by: Christophe Mutricy <xtophe@videolan.org>
(cherry picked from commit f067ff20)

configure.ac

@@ -2499,6 +2499,8 @@ dnl Need to test libcdio and libvcdinfo for a number of things. Do it now.
 AC_ARG_ENABLE(libcdio,
   [  --enable-libcdio        CD input and control library support (default enabled)])
 
+AC_ARG_ENABLE(vcdinfo,
+  [  --enable-libvcdinfo     VCD information library support (default enabled)])
 
 have_libcdio=no
 have_libvcdinfo=no
@@ -2510,11 +2512,14 @@ then
      [Define if you have libcdio 0.78.2 or greater installed]),
      [AC_MSG_WARN(CD Reading and information library not found)])
 
+  if test "${enable_vcdinfo}" != "no"
+  then
     PKG_CHECK_MODULES(VCDINFO, libvcdinfo >= 0.7.22,
        [have_libvcdinfo=yes
        AC_DEFINE(HAVE_VCDINFO, 1, 
        [Define if you have libvcdinfo 0.7.22 or greater installed])],
        [AC_MSG_WARN(VCD information library not found)])
+  fi
 fi
 
 dnl