Fix building without X11 but with Lua
Make diskio work with /dev/disk/*/* paths

This uses the POSIX.1-2008 function realpath; if it does not comply with
the standard, bad things will happen (unspecified behaviour). Linux does
it right from the beginning.
Set uninitialized inotify_fd to -1, not 0

Currently we set inotify_fd to the value 0 when inotify_fd hasn't been
created yet, or after we close it. But 0 is a valid fd, and we check
for the value -1 to see if it's been initialized. So, if inotify
support is compiled in, but we disable_auto_reload, we can end up
closing fd 0. This can screw up various other things in weird ways,
including that exec'd processes appear to have an invalid stdin.

So, set inotify_fd to -1 to clear all of this up.
(cherry picked from commit f670e70d7c0ffcc602f40aa1856fe085e5800455)
Merge pull request #15 from Tucos/1.9.1

Small fixes
Merge pull request #16 from horazont/1.9.1

Make diskio work with /dev/disk/*/* paths
Merge pull request #23 from adeason/1.9.1_inotifyfd

Set uninitialized inotify_fd to -1, not 0
Add build file.