egl: Do not unload drivers.

When the driver is the last reference to libEGL.so, unloading it will
cause libEGL.so to be unmapped and give problems.  Disable the unloading
for now.  Still have to figure out the right timing to unload drivers.

src/egl/main/egldriver.c

@@ -186,11 +186,22 @@ _eglLoadModule(_EGLModule *mod)
 static void
 _eglUnloadModule(_EGLModule *mod)
 {
+#if defined(_EGL_OS_UNIX)
    /* destroy the driver */
    if (mod->Driver && mod->Driver->Unload)
       mod->Driver->Unload(mod->Driver);
+
+   /*
+    * XXX At this point (atexit), the module might be the last reference to
+    * libEGL.  Closing the module might unmap libEGL and give problems.
+    */
+#if 0
    if (mod->Handle)
       close_library(mod->Handle);
+#endif
+#elif defined(_EGL_OS_WINDOWS)
+   /* XXX Windows unloads DLLs before atexit */
+#endif
 
    mod->Driver = NULL;
    mod->Handle = NULL;
@@ -670,12 +681,7 @@ _eglUnloadDrivers(void)
 {
    /* this is called at atexit time */
    if (_eglModules) {
-#if defined(_EGL_OS_UNIX)
       _eglDestroyArray(_eglModules, _eglFreeModule);
-#elif defined(_EGL_OS_WINDOWS)
-      /* XXX Windows unloads DLLs before atexit */
-      _eglDestroyArray(_eglModules, NULL);
-#endif
       _eglModules = NULL;
    }
 }