Working around netifaces segfault on FreeBSD

netifaces.gateways() function segmentation fault on FreeBSD, making
Glances unusable. As a workaround, just disable netifaces on FreeBSD.
See https://bitbucket.org/al45tair/netifaces/issues/15.

Fixes #670.

glances/core/glances_autodiscover.py

@@ -35,7 +35,7 @@ except ImportError:
     zeroconf_tag = False
 
 # Import Glances libs
-from glances.core.glances_globals import appname
+from glances.core.glances_globals import appname, is_freebsd
 from glances.core.glances_logging import logger
 
 # Zeroconf 0.17 or higher is needed
@@ -194,6 +194,9 @@ class GlancesAutoDiscoverClient(object):
             except socket.error as e:
                 logger.error("Cannot start zeroconf: {0}".format(e))
 
+            # XXX FreeBSD: Segmentation fault (core dumped)
+            # -- https://bitbucket.org/al45tair/netifaces/issues/15
+            if not is_freebsd:
                 try:
                     # -B @ overwrite the dynamic IPv4 choice
                     if zeroconf_bind_address == '0.0.0.0':

glances/core/glances_globals.py

@@ -33,6 +33,7 @@ is_py3 = sys.version_info >= (3, 3)
 # Operating system flag
 # Note: Somes libs depends of OS
 is_bsd = sys.platform.find('bsd') != -1
+is_freebsd = sys.platform.startswith('freebsd')
 is_linux = sys.platform.startswith('linux')
 is_mac = sys.platform.startswith('darwin')
 is_windows = sys.platform.startswith('win')

glances/plugins/glances_ip.py

@@ -19,16 +19,21 @@
 
 """IP plugin."""
 
-# Import system libs
+# Import Glances libs
+from glances.core.glances_globals import is_freebsd
+from glances.core.glances_logging import logger
+from glances.plugins.glances_plugin import GlancesPlugin
+
+# XXX FreeBSD: Segmentation fault (core dumped)
+# -- https://bitbucket.org/al45tair/netifaces/issues/15
+if not is_freebsd:
     try:
         import netifaces
         netifaces_tag = True
     except ImportError:
         netifaces_tag = False
-
-# Import Glances libs
-from glances.core.glances_logging import logger
-from glances.plugins.glances_plugin import GlancesPlugin
+else:
+    netifaces_tag = False
 
 
 class Plugin(GlancesPlugin):