Handle named function arguments correctly.
Fix a few while statement bugs.

Namely:
* Need to put parens around all expressions, even "atomic" ones like
  integer constants.
* Should handle empty bodies correctly.
New example: unix cat(1) command.
Build system/example housecleaning.

* Makefile can build examples
* example binaries are in .gitignore
* removed have_function_calls example; this would more useful as a test;
  it isn't very informative as an example.
Implement char literals