--with-logpath-by-env fails to compile unless --with-logpath is also specified
Both --with-logpath and --with-logpath-by-env can be specified in the same build. However, it should also be possible to use --with-logpath-by-env without the --with-logpath argument. Right now this causes a compile error.
The workaround is to specify a --with-logpath, even if you don't intend to use it.