Add the GLIB_AVAILABLE_IN_ALL annotation to all old functions (that
haven't already been annotated with the GLIB_AVAILABLE_IN_* macros or a
deprecation macro).
If we discover in the future that we cannot use only one macro on
Windows, it will be an easy sed patch to fix that.
https://bugzilla.gnome.org/show_bug.cgi?id=688681
gvariant-internal.h was defining GLIB_COMPILATION so that it could
include individual headers, but this broke tests/gvariant on windows
because setting GLIB_COMPILATION changes the definition of GLIB_VAR,
causing external variables to not be found. Fix this by having it
define __GLIB_H_INSIDE__ instead.
https://bugzilla.gnome.org/show_bug.cgi?id=688109
Merge GVariant variable arguments support and put it under tests.
Also, remove the hack of the test case directly '#include'ing .c files
from glib/. Instead, create a non-installed gvariant-internal.h that
the tests can include and make the symbols in it visible on the symbol
table of the shared library. These symbols (as they are present in no
installed header files) are not part of the API of GLib.
Increase test coverage in a few other areas.