I figured it out!

theres a mini configure.ac generated by distrib/configure.ac.in thats used to setup the ghc settings file at install time!

https://github.com/cartazio/ghc/tree/cpp_silly-contrib-configure-in is my current set of patches, though it needs some rebasing, cleanup, and code review etcetc, 

will update the (admittedly too long )  trac ticket with this info 


On Mon, Mar 24, 2014 at 6:39 AM, Malcolm Wallace <malcolm.wallace@me.com> wrote:

On 23 Mar 2014, at 20:33, Carter Schonwald wrote:

> Hey all, I'm trying to get my CPP_Setttings patch to validate,
> and i'm trying to understand why my validate is failing. At this point im stumped and I really could  use some help!


This looks like the key information:

> Building xhtml-3000.2.1...
> Preprocessing library xhtml-3000.2.1...
> ghc: could not execute:

Ghc is reporting that it could not execute "".  This suggests the commandline for external preprocessing is incorrectly formed.

Regards,
    Malcolm