Xcode 5.0.2 doesn't seem to like header search paths which look like this:
HEADER_SEARCH_PATHS = (something, artichoke, guacamole);
What does work is:
HEADER_SEARCH_PATHS = ("something", "artichoke", "guacamole");
Changing this line in XCodeProjectExporter::getHeaderSearchPaths:
else if (s.containsAnyOf ("${}()@&~+-=<>\t;\r\n"))
to
else
Seems to solve it.
The issue can be reproduced with projects using a header search path that does not contains a `$` sign or one of the other operators which currently cause Introjucer to put quotes on the path.