gstreamer-plugins-base 1.14.4 doesn't build on GCC 4.5

The build fails with:

In file included from ../../../../gst-libs/gst/gl/gl.h:28:0,
                 from gstglcontext_glx.c:37:
../../../../gst-libs/gst/gl/gstgldebug.h:28:33: error: redefinition of typedef 'GstGLAsyncDebug'
../gstgl_fwd.h:107:33: note: previous declaration of 'GstGLAsyncDebug' was here

In the following environment:
gstreamer 1.14.4
custom Linux distro (32-bit)
GCC 4.5.3

This is because duplicated typedefs are not allowed in C99, and GCC 4.5.3 doesn't support C11.