-/* Concatenate two pathname components, DIR and BASE, in
- newly-allocated storage and return the result. Return 0 if out of
- memory. Add a slash between DIR and BASE in the result if neither
- would contribute one. If each would contribute at least one, elide
- one from the end of DIR. Otherwise, simply concatenate DIR and
- BASE. In any case, if BASE_IN_RESULT is non-NULL, set
+/* Concatenate two pathname components, DIR and ABASE, in
+ newly-allocated storage and return the result.
+ The resulting file name F is such that the commands "ls F" and "(cd
+ DIR; ls BASE)" refer to the same file, where BASE is ABASE with any
+ file system prefixes and leading separators removed.
+ Arrange for a directory separator if necessary between DIR and BASE
+ in the result, removing any redundant separators.
+ In any case, if BASE_IN_RESULT is non-NULL, set