[tlbuild] trying to add package

[Bob Tennent]

I'm trying to add a package xml2pmx to (a local copy of)
texlive. So I'm following "Adding a new program module" and
"Build one package" in the tlbuild documentation.

The last apparently successful step (executed in Work) was

  ../configure --disable-all-pkgs --enable-xml2pmx -C CFLAGS=-g CXXFLAGS=-g

but when I do make (in Work):

  configure: error: cannot find sources (obx.h) in ../../../utils/xml2pmx
  === configuring in xml2pmx failed

yet obx.h (and other source files) are in xml2pmx-src.

The Makefile.am in xml2pmx has

  xml2pmx_SOURCES = \
        @XML2PMX_TREE@/obx.h \
        ...

so I'm conjecturing that @XML2PMX_TREE@ isn't defined, but I
don't know where that happens. Can anyone help?

Bob T.