setup.py: Add 'mercurial' as include dir for the inotify compiler.
This patch adds access to util.h for the inotify C module by adding the
"mercurial" directory as an include dir, enabling access to the macros defined
in util.h.
#!/bin/sh
mkdir t
cd t
hg init
echo a > a
hg add a
hg commit -m test -d "1000000 0"
hg history
hg manifest --debug
hg cat a
hg verify