If compiled with -Dgstreamer:gst_debug=false and we have
GST_REMOVE_DISABLED defined we will get the following compiler error:
```
[...]/libgstreamer-1.0.so.0.2100.0.p/gst.c.o: in function `gst_deinit':
[...]/gst/gst.c:1258: undefined reference to `_priv_gst_debug_cleanup'
[...] hidden symbol `_priv_gst_debug_cleanup' isn't defined
```
Add the missing define guard to avoid this.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/2648>
GLib guarantees libintl is always present, using proxy-libintl as
last resort. There is no need to mock gettex API any more.
This fix static build on Windows because G_INTL_STATIC_COMPILATION must
be defined before including libintl.h, and glib does it for us as part
as including glib.h.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/2028>
