setup.py: add chroot detection

Fixes #471.

setup.py

@@ -6,6 +6,8 @@ import sys
 
 from setuptools import setup
 
+is_chroot = os.stat('/').st_ino != 2
+
 
 def get_data_files():
     data_files = [
@@ -15,15 +17,16 @@ def get_data_files():
         ('share/man/man1', ['man/glances.1'])
     ]
 
-    if os.name == 'posix' and os.getuid() == 0:  # Unix-like + root privileges
+    if hasattr(sys, 'real_prefix'):  # virtualenv
+        conf_path = os.path.join(sys.prefix, 'etc', 'glances')
+    elif os.name == 'posix' and (os.getuid() == 0 or is_chroot):
+        # Unix-like + root privileges/chroot environment
         if 'bsd' in sys.platform:
             conf_path = os.path.join(sys.prefix, 'etc', 'glances')
         elif 'linux' in sys.platform:
             conf_path = os.path.join('/etc', 'glances')
         elif 'darwin' in sys.platform:
             conf_path = os.path.join('/usr/local', 'etc', 'glances')
-    elif hasattr(sys, 'real_prefix'):  # virtualenv
-        conf_path = os.path.join(sys.prefix, 'etc', 'glances')
     elif 'win32' in sys.platform:  # windows
         conf_path = os.path.join(os.environ.get('APPDATA'), 'glances')
     else:  # Unix-like + per-user install