Bash builtin integration

[Wu Ming]

Trying to compile bash builtin on macOS with bash 5.2 from brew and recutils 
1.9 from sources.

Files generated in bash/ are readrec.[o,lo,la] and testrec.[o,lo,la].

readrec.la defines library_names='readrec.0.so readrec.so’

but .so library is not generated. So I can not enable the builtin as requested 
https://www.gnu.org/software/recutils/manual/html_node/Bash-Builtins.html#Bash-Builtins

Please advise.