setup.py: skip inotify if there's no inotify_add_watch
Debian Etch doesn't include a sys/inotify.h header, which makes it
impossible to compile _inotify.c, making hg uninstallable.
The cc.has_function() method is implemented by trying to compile a
simple C program. Since there's no redirection involved all error
messages are sent to the terminal. This is not particularly pretty
but at least it allows the installation to complete.
adding bar
adding foo
% state dump
a 0 -1 baz
n 644 0 foo
r 0 0 bar
% status
A baz
R bar
C foo
% state dump
n 666 -1 bar
n 666 -1 foo
% status
! bar
? baz
C foo