Checking for 'main' in libgd

Hi there,

I have an application "graphviz" here that does check for the presence
of the "main" function in libgd:

| AC_CHECK_LIB(gd,main,[
|   GD_LIBS="$GD_LDFLAGS -lgd $GD_LIBS"
|   AC_DEFINE_UNQUOTED(HAVE_LIBGD,1,[Define if you have the GD library])
|   use_gd="Yes"
| ],[
|   AC_MSG_WARN(Optional GD library not available)
|   use_gd="No (library not found)"
| ], $GD_LIBS)

This check for "main" fails and thus the application assumes, libgd is
not available. Is there good reason to check for "main" in libgd, or is
that simply a bug?

Br,
Dirk.