+        #~`(,(string-append "CPPFLAGS=-DGUIX_RKTIO_BIN_SH="
+                            #$(file-append (this-package-input
"bash-minimal")
+                                           "/bin/sh"))

As with chez-scheme, I do think using a Racket-agnostic macro name is
helpful here.

I'm planning to respond in the other thread about the possibility of a truly generic macro name, but I hope it doesn't need to become an issue blocking this patch series. For now, I'm not entirely sure what "Racket-agnostic" means; the bottom line for my is I think it would be absurdly awful to have to write, e.g. if cross-compiling using `distro-build` with the top-level Makefile:

    ./configure CPPFLAGS="GUIX_RKTIO_BIN_SH=/input/bin/sh GUIX_ZUO_BIN_SH=/input/bin/sh GUIX_CHEZ_BIN_SH=/input/bin/sh" CPPFLAGS_FOR_BUILD="GUIX_RKTIO_BIN_SH=/native-input/bin/sh GUIX_ZUO_BIN_SH=/native-input/bin/sh GUIX_CHEZ_BIN_SH=/native-input/bin/sh"

Example: GUIX_SH=/inputs/bin/sh.

I haven't been following the discussion on the other patches, but didn't I give an example of something independent of the Racket component in use and even independent of Racket itself? See the suggestion of using the already existing _PATH_BSHELL from <paths.h>. It's even not Guix-specific, apparently it's a BSD-ism!

Maxime.