Remove "nodelete" linker flag now that we use sd-bus and not dbus-glib,
so that libraries that pam_fprintd links to can be unloaded.
This was added because GLib's type system expects to be initialised
once and only once per process, and re-loading this type system when it
had already been initialised caused crashes.
This pam plugin never used GDBus because it transparently uses threads
which do not work well with a lot of PAM applications. But even settling
on the "still better to use than plain dbus library" dbus-glib wasn't
without problems, as any use or initialisation of GIO sockets would
modify signal handler for signals such as SIGPIPE (see gio/gsocket.c).
Many years later, sd-bus is a more modern alternative to the bare dbus
library with a better API.
This includes:
- Removing use of gboolean, guint, g_new0() and many glib string helpers
- Simplifying debug logging
- Marking user-facing messages to be translated
The PAM module uses dbus-glib, static gobject types, etc,
so it really can't get unloaded.
This commit adds some linker-fu to keep it resident even
after the pam module closes.
- Use D-Bus native properties instead of a GetProperties call.
- Fix a number of front-ends by registering the right signals and
marshallers following the "done" signal argument addition
- Fix VerifyStart call in the pam module
