EGL: remove the dlopen() hack

It only worked for non-ES OpenGL and if the libGL development files
were installed (otherwise "libGL.so" does not exist). So let Mesa fix
their bugs and stop caring about them:
https://bugs.freedesktop.org/show_bug.cgi?id=34476

In the mean time, you can use VLC and EGL with:

 # LD_PRELOAD=/usr/lib/libGL.so vlc

modules/video_output/Modules.am

@@ -115,7 +115,7 @@ libegl_plugin_la_SOURCES = egl.c
 libegl_plugin_la_CFLAGS = $(AM_CFLAGS) $(EGL_CFLAGS)
 libegl_plugin_la_LIBADD = $(AM_LIBADD) $(EGL_LIBS)
 if !HAVE_WIN32
-libegl_plugin_la_LIBADD += -ldl $(X_LIBS) $(X_PRE_LIBS) -lX11
+libegl_plugin_la_LIBADD += $(X_LIBS) $(X_PRE_LIBS) -lX11
 endif
 libegl_plugin_la_DEPENDENCIES =
 EXTRA_LTLIBRARIES += libegl_plugin.la

modules/video_output/egl.c

@@ -34,7 +34,6 @@
 #include <vlc_vout_window.h>
 #ifdef __unix__
 # include <vlc_xlib.h>
-# include <dlfcn.h>
 #endif
 
 /* Plugin callbacks */
@@ -127,20 +126,6 @@ static int Open (vlc_object_t *obj, const struct gl_api *api)
     gl->sys = sys;
     sys->display = dpy;
 
-#ifdef __unix__
-    /* XXX Explicit hack!
-     * Mesa EGL plugins (as of version 7.8.2) are not properly linked to
-     * libEGL.so even though they import some of its symbols. This is
-     * typically not a problem. Unfortunately, LibVLC loads plugins as
-     * RTLD_LOCAL so that they do not pollute the namespace. Then the
-     * libEGL symbols are not visible to EGL plugins, and the run-time
-     * linker exits the whole process. */
-    if (dlopen ("libEGL.so", RTLD_GLOBAL|RTLD_NOW) == NULL)
-        msg_Warn (gl, "libEGL cannot be loaded. Process might crash.");
-    if (dlopen ("libGL.so", RTLD_GLOBAL|RTLD_NOW) == NULL)
-        msg_Warn (gl, "libGL cannot be loaded. Process might crash.");
-#endif
-
     EGLint major, minor;
     if (eglInitialize (dpy, &major, &minor) != EGL_TRUE)
     {