#3 Including individual glib headers no longer supported

[quadrispro]

Hi,

including invidiual glib headers has been deprecated for several years.

Starting with glib 2.32 it is now mandatory to include glib.h instead
of individual headers [1], or the compiler will generate an error.

With the notable exception of:
glib/gi18n.h
glib/gi18n-lib.h
glib/gprintf.h
glib/gstdio.h
Those header files are still meant to be included separately.

[quadrispro]