Obsolete dependency on gthread-2.0

[tbeu]

In lcm.c there is if (!g_thread_supported ()) g_thread_init (NULL); Since g_thread_supported is defined to 1, function g_thread_init is never called and removed by the optimizing compiler. It anyway would do nothing, since in gthread-impl.c it is:

void g_thread_init (gpointer init) {
  if (init != NULL)
    g_warning ("GThread system no longer supports custom thread implementations.");
}

Therefore the dependency on gthread-2.0 can be removed.

[tprk77]

The GLib threading system used to be initialized with g_thread_init(). This is no longer necessary. Since version 2.32, the GLib threading system is automatically initialized at the start of your program, and all thread-creation functions and synchronization primitives are available right away.

So you're right, g_thread_supported and g_thread_init are both deprecated since 2012. We should be able to remove this code. But I'm a little confused about removing the gthread dependency, as it seems to built into glib now. I'll go take a look.

[tprk77]

Ok, so I think I see what you mean. In configure.ac for example we check:

PKG_CHECK_MODULES(GLIB,[glib-2.0 >= 2.0.0 gthread-2.0 >= 2.0.0],,[AC_MSG_ERROR([LCM requires GLib >= 2.0])])

But we might be able to change this to something like:

PKG_CHECK_MODULES(GLIB,[glib-2.0 >= 2.32.0],,[AC_MSG_ERROR([LCM requires GLib >= 2.32])])

Well, I'm kind of surprised this is a problem for you. On Ubuntu 16.04, glib-2.0 is still packaged with a libgthread-2.0.so. Are you having a specific linker problem?