In the configure script we check for the presence of several basic tools, like grep, sed, echo etc, and assign variables for them. In the makefiles we are very diligent with always using the tools through these variables to make sure we have a well functioning version of the tool at hand. In many places in the configure script, we have been sloppy with this.

I recently stumbled over this because we change the PATH variable in parts of the script (typically when looking for the toolchain) which can then potentially change which instance of the tool that is being run unless the resolved variables are used. The current build works anyway, but we really should clean this up to make it more robust.