The configure script has a check to see if RTLD_GLOBAL works properly or not. 
This check does not work, because it detects that RTLD_GLOBAL doesn't work
properly under NetBSD, while it does.  The problems of this are exposed later in
other libraries using glib (specially, I got crazy to see why gstreamer did not
work at all on my computer).

Why the check breaks... well, it uses libpthread.so as a test case.  In NetBSD,
this library can't be loaded at runtime by a non-threaded application.  That is,
if you have a program that's not linked with libpthread, opening a module at
runtime that uses it results in a coredump.  This is because the program startup
code is different for threaded applications.  So, the check in configure breaks,
and glib is built without RTLD_GLOBAL support (a thing that you won't notice
until it's very late).  Eww.

I've fixed it by changing the check to use 'libintl' as a test case (which is
required anyway by glib).  It works.  This is what has been done in pkgsrc (the
NetBSD packaging system) to fix this issue:

    http://mail-index.netbsd.org/pkgsrc-changes/2004/04/06/0004.html

The attached patch does the same.

Furthermore, it could be a good idea to show a big warning from glib when a
program tries to g_module_load a library with global binding, if it's not
available (because the application won't work, probably).