gnu: yadifa: Strip spurious store references.

* gnu/packages/dns.scm (yadifa)[arguments]: Add an
‘omit-spurious-references’ phase.

gnu/packages/dns.scm

@@ -782,6 +782,13 @@ (define-public yadifa
            (lambda _
              (substitute* "Makefile.in"
                ((" (etc|var)") ""))
+             #t))
+         (add-after 'configure 'omit-spurious-references
+           (lambda _
+             ;; The many Makefile.in grep this(!) to #define BUILD_OPTIONS.
+             (substitute* "config.log"
+               (("(=/gnu/store/)[^-]*" _ match)
+                (string-append match "...")))
              #t)))
        #:configure-flags
        (list "--sysconfdir=/etc"