/bin/sh in package definitions

[Andy Tai]

Hi, currently package definitions often need to patch references to
/bin/sh as common in package sources or makefiles to make it refer to
the actual bash shell used in Guix in /gnu/store/... somewhere.

question 1:   is there a way, to simulate /bin/sh using container or
some such set up so the actual shell used by Guix can appear as
/bin/sh in the package build process?  (sorry if this is a wild
question)

question 2: (if question 1 is not possible) in guile, how to replace
only occurrences of /bin/sh, not substring "/bin/sh" in some strings
like /usr/bin/shsomethingsomethng, in the "patch" stage of package
building?