Build errors - might be bogus

[Doug Smythies]

When compiling the installation guide, there are errors. For example:

Architecture: amd64
Info: creating temporary profiled .xml file...
/home/doug/install/z/en/boot-installer/x86.xml:291: element sect2: validity error : ID boot-tftp already defined
  <sect2 arch="x86" id="boot-tftp"><title>Booting with TFTP</title>
                                  ^
/home/doug/install/z/en/boot-installer/ia64.xml:318: element sect2: validity error : ID boot-tftp already defined
  <sect2 arch="ia64" id="boot-tftp"><title>Booting with TFTP</title>
                                   ^

However, and as far as I have been able to determine, they are bogus.
I see them also in the build logs on launchpad.
I have not been able to determine that there is actually any real problem.
I never had this issue when I compiled using a trusty computer, nor do I see the same errors in the trusty launchpad build logs, but I do get the errors if I revert to revision 517 (back to an old trusty version), but compile with a xenial sever computer.

Conclusion: At this point I think, but am not sure, the root issue is in the compile tools and not the source code itself.