...as obviously I lack the skills to understand the log etc
I don't think it's that - something else must be wrong, all that's needed is compiletc and Xorg-7.6-dev.
There shouldn't be any need for libxcb and, as per config.log, the configure script is not looking for it.
To understand better where you stand when compiling, I wouldn't recommend to have compiletc or any *-dev extensions "onboot" or "ondemand", but rather to load them one by one from a terminal window to check for confirmation that they're loaded, any errors, etc.
Give it another try - you never know, it might just work this time