Compiling libev on Ubuntu Edgy Eft

On Ubuntu Edy Eft sys/inotify.h does not define IN_DONT_FOLLOW
(however linux/inotify.h does), so adding the check below will
circumvent compilation errors.

diff --git a/src/extconf.rb b/src/extconf.rb
index 2175fab..91bd44a 100644
--- a/src/extconf.rb
+++ b/src/extconf.rb
@@ -27,7 +27,7 @@ if have_header('port.h')
   flags << '-DEV_USE_PORT'
end

-if have_header('sys/inotify.h')
+if have_header('sys/inotify.h') and have_var('IN_DONT_FOLLOW', 'sys/
inotify.h')
   flags << '-DEV_USE_INOTIFY'
end

Michael