[Chicken-hackers] Patch to make CHICKEN 4.11.0 more compatible with Android/Termux

Dear chicken-hackers, I occasionally use CHICKEN under Android on my Nexus 9 tablet. I use the Termux App (http://termux.com), which is a terminal emulator and package manager for Android. I'd like to submit the attached patch for review. The environment has the following pecularities: -

Re: [Chicken-hackers] [PATCH 0/5][5] Generalize port directionality and add basic refinement types

* John Cowan [160709 19:03]: > > For situations when it's desirable to expose only one end of a > > pair, we could create a procedure like "extract-input-port" and > > "extract-output-port" from a bidirectional port. I'm not sure what > > good names would be for these. >