Log Message:
Updated wxGTK30 to 3.0.3.

Carry forward libtool patch from 3.0.2, with LDFLAGS changes
included.

This is a bug fix release with no significant new features compared
to the previous 3.0.x releases and compatible with them at both the
API and the ABI level (i.e. all applications linked against earlier
3.0.x DLLs or shared libraries will continue to work when using
3.0.3 libraries).

The full list of changes in this release is available at

https://raw.githubusercontent.com/wxWidgets/wxWidgets/v3.0.3/docs/changes.txt

(starting from the line 583, or search for "3.0.3" in this file),
here are some selected ones:

* In all ports:
 - Support requestion modern (3.x+) OpenGL version in wxGLCanvas.
 - Fix using wxHTTP and wxFTP from worker thread.

* In wxGTK:
 - Support for Gstreamer 1.0 in wxMediaCtrl, in addition to obsolete 0.x.
 - Several fatal bug fixes for GTK+ 3.