Hi Mark, On Thu, 2 Mar 2017, Mark Phillips wrote: > I am building git from source using gcc 4.8.5 on 64 bit linux. > > I am sorry the log info is not very helpful, please tell me how to get > more information about what is going wrong and I will collect the info > for you! Well, you could provide a Minimal, Complete and Verifiable Example (http://stackoverflow.com/help/mcve): most likely, the error depends on particular features of your current HEAD, or environment variables. Because i do *not* get that error if I run `git difftool -d HEAD~`. So it is not so much about collecting info as about distilling your use case into an example that allows other developers to reproduce the problem, and subsequently fix it. Ciao, Johannes