I figured it out thanks to the people on IRC:
(arguments
`(;; Roundup has no check target (It does have a `test` target, but some
;; of its tests fail intentionally, bringing the entire build process
;; down)
#:tests? #f
;; Explicitly set the shell because otherwise this value will be empty
#:make-flags
'("SHELL=bash")
#:phases
(modify-phases %standard-phases
(add-before 'configure 'fix-configure
;; getconf will return a static path, which will not contain the
;; value adjusted by Guix
(λ _ (substitute* "configure" (("getconf PATH") "echo $PATH"))))
(replace 'configure
;; Roundup is using a hand-written configure script which will
choke
;; on the default configure flags. Therefore we invoke it with our
;; own flags.
(lambda* (#:key outputs (configure-flags '()) #:allow-other-keys)
(let ((out (assoc-ref outputs "out")))
(apply invoke
`("./configure"
,(string-append "--prefix=" out)
"--sysconfdir=/etc"
,@configure-flags))))))))
Ludovic Courtès wrote:
> Indeed. Could it be that ‘configure’ overrides PATH, setting it to,
> say, /bin:/usr/bin? (You mentioned ‘getconf PATH’ yesterday on IRC,
> perhaps that’s related?)
>
> HTH,
> Ludo’.
