The following checks in mm_modem_firmware_select() and
mm_modem_firmware_select_sync() could result in a NULL pointer
dereference if `unique_id' is NULL:
g_return_if_fail (unique_id != NULL || unique_id[0] == '\0')
g_return_val_if_fail (unique_id != NULL || unique_id[0] == '\0', FALSE)
This patch fixes the checks to properly verify that `unique_id' is
neither NULL nor an empty string.
Both the ModemManager daemon and the mmcli will now include `libmm-glib.h' only.
We also handle two new special `_LIBMM_INSIDE_MM' and `LIBMM_INSIDE_MMCLI'
symbols, which if included before the `libmm-glib.h' library allow us to:
* Don't include the libmm-glib high level API in the ModemManager daemon, as
the object names would clash with those in the core.
* Define some of the methods of helper objects to be included only if compiling
ModemManager daemon or the mmcli.
