g_assert() uses G_LIKELY(), which in turn uses _G_BOOLEAN_EXPR().
As glib's version of _G_BOOLEAN_EXPR() uses a local variable
_g_boolean_var_, we cannot nest a G_LIKELY() inside a G_LIKELY(),
or inside a g_assert(), or a g_assert() inside a g_assert().
Workaround that, by redefining the macro.
I already encountered this problem before, when having a nm_assert()
inside a ({...}) block, inside a g_assert(). Then I just avoided that
combination, but this situation is quite easy to encounter.
The "shared" directory contains files that are possibly used by all components
of NetworkManager repository.
Some of these files are even copied as-is to other projects (VPN plugins, nm-applet)
and used there without modification. Move those files to a separate directory.
By moving them to a common directory, it is clearer that they belong
together. Also, you can easier compare the copied versions to their
original via
$ diff -r ./shared/nm-utils/ /path/to/nm-vpn-plugin/shared/nm-utils/
