building: recutils bash builtins/readrec.so; ./configure --with-bash-headers=... # fails

[bug-bash]

No response today from bug-recutils:

    http://lists.gnu.org/archive/html/bug-recutils/2017-11/msg00004.html

For the ./configure, I untarred the latest bash source into a subdir, and set 
--with-bash-headers=
to that pathname. 

Perhaps someone with an understanding of GNU configure/autoconf etc could take
a look and give me some hints.  Or tell me where to ask.

--
thanks!