gnu: Use 'search-input-file' when looking for executables.

* gnu/packages/admin.scm (isc-dhcp): Use 'search-input-file' when
looking for executables.
* gnu/packages/audio.scm (ableton-link): Likewise.
* gnu/packages/benchmark.scm (fio): Likewise.
* gnu/packages/bioinformatics.scm (roary): Likewise.
(ngless): Likewise.
* gnu/packages/boost.scm (boost-for-irods): Likewise.
* gnu/packages/bootloaders.scm (grub): Likewise.
(grub-efi): Likewise.
* gnu/packages/chemistry.scm (inchi): Likewise.
* gnu/packages/dictionaries.scm (ding): Likewise.
* gnu/packages/dlang.scm (ldc): Likewise.
* gnu/packages/education.scm (childsplay): Likewise.
* gnu/packages/emacs-xyz.scm (emacs-hyperbole): Likewise.
(emacs-haskell-mode): Likewise.
(emacs-auctex): Likewise.
(emacs-ggtags): Likewise.
(emacs-graphviz-dot-mode): Likewise.
(emacs-flycheck-grammalecte): Likewise.
(emacs-counsel-notmuch): Likewise.
(emacspeak): Likewise.
(emacs-exwm): Likewise.
(emacs-exwm-x): Likewise.
(emacs-treemacs): Likewise.
(emacs-telega): Likewise.
(emacs-exiftool): Likewise.
* gnu/packages/emulators.scm (higan): Likewise.
* gnu/packages/engineering.scm (freehdl): Likewise.
(librepcb): Likewise.
* gnu/packages/entr.scm (entr): Likewise.
* gnu/packages/file-systems.scm (libeatmydata): Likewise.
(xfstests): Likewise.
(mergerfs): Likewise.
(mergerfs-tools): Likewise.
* gnu/packages/finance.scm (monero-gui): Likewise.
* gnu/packages/flashing-tools.scm (flashrom): Likewise.
* gnu/packages/fontutils.scm (fontforge): Likewise.
* gnu/packages/game-development.scm (python2-renpy): Likewise.
* gnu/packages/games.scm (opensurge): Likewise.
(xboard): Likewise.
(hyperrogue): Likewise.
(flare-game): Likewise.
(chessx): Likewise.
* gnu/packages/geo.scm (grass): Likewise.
* gnu/packages/glib.scm (glib): Likewise.
* gnu/packages/gnome.scm (mm-common): Likewise.
(network-manager-openvpn): Likewise.
(network-manager-vpnc): Likewise.
(network-manager-openconnect): Likewise.
(apostrophe): Likewise.
* gnu/packages/gnupg.scm (pius): Likewise.
(jetring): Likewise.
* gnu/packages/gnuzilla.scm (icedove): Likewise.
* gnu/packages/golang.scm (go-1.4): Likewise.
* gnu/packages/graphviz.scm (xdot): Likewise.
* gnu/packages/guile-xyz.scm (jupyter-guile-kernel): Likewise.
* gnu/packages/haskell-xyz.scm (ghc-hindent): Likewise.
* gnu/packages/ibus.scm (ibus): Likewise.
* gnu/packages/image.scm (phockup): Likewise.
* gnu/packages/irc.scm (quassel): Likewise.
* gnu/packages/java.scm (drip): Likewise.
(ant-bootstrap): Likewise.
(tla2tools): Likewise.
* gnu/packages/julia.scm (julia): Likewise.
* gnu/packages/less.scm (lesspipe): Likewise.
* gnu/packages/libreoffice.scm (libreoffice): Likewise.
* gnu/packages/linux.scm (fuse): Likewise.
(lm-sensors): Likewise.
(bluez): Likewise.
(fakeroot): Likewise.
(inputattach): Likewise.
* gnu/packages/lisp-xyz.scm (sbcl-cl-diskspace): Likewise.
* gnu/packages/lisp.scm (lisp-repl-core-dumper): Likewise.
* gnu/packages/lua.scm (fennel): Likewise.
* gnu/packages/lxde.scm (spacefm): Likewise.
* gnu/packages/mail.scm (public-inbox): Likewise.
* gnu/packages/maths.scm (hdf-java): Likewise.
(maxima): Likewise.
(frama-c): Likewise.
* gnu/packages/messaging.scm (libgadu): Likewise.
* gnu/packages/music.scm (denemo): Likewise.
(curseradio): Likewise.
* gnu/packages/netpbm.scm (netpbm): Likewise.
* gnu/packages/networking.scm (blueman): Likewise.
(squid): Likewise.
(aircrack-ng): Likewise.
* gnu/packages/node.scm (node): Likewise.
(node-llparse-frontend-bootstrap): Likewise.
(node-llparse-bootstrap): Likewise.
(llhttp-bootstrap): Likewise.
(node-lts): Likewise.
* gnu/packages/ocaml.scm (ocaml-4.11): Likewise.
(opam): Likewise.
(ocaml-graph): Likewise.
* gnu/packages/orpheus.scm (orpheus): Likewise.
* gnu/packages/password-utils.scm (password-store): Likewise.
* gnu/packages/python.scm (pypy3): Likewise.
* gnu/packages/qt.scm (qt5ct): Likewise.
* gnu/packages/radio.scm (libosmo-dsp): Likewise.
* gnu/packages/ruby.scm (ruby-pandoc-ruby): Likewise.
* gnu/packages/rust.scm (rust-1.30): Likewise.
* gnu/packages/screen.scm (byobu): Likewise.
* gnu/packages/statistics.scm (r-with-tests): Likewise.
* gnu/packages/suckless.scm (surf): Likewise.
* gnu/packages/syndication.scm (gfeeds): Likewise.
* gnu/packages/telephony.scm (mumble): Likewise.
* gnu/packages/terminals.scm (alacritty): Likewise.
* gnu/packages/tex.scm (texlive-bin): Likewise.
* gnu/packages/uml.scm (plantuml): Likewise.
* gnu/packages/version-control.scm (python-git-multimail): Likewise.
(gitolite): Likewise.
(hg-commitsigs): Likewise.
(git-when-merged): Likewise.
(git-imerge): Likewise.
(gita): Likewise.
* gnu/packages/video.scm (you-get): Likewise.
* gnu/packages/vim.scm (eovim): Likewise.
* gnu/packages/virtualization.scm (qemu): Likewise.
(virt-manager): Likewise.
(criu): Likewise.
* gnu/packages/vpn.scm (strongswan): Likewise.
(xl2tpd): Likewise.
* gnu/packages/wm.scm (i3lock-fancy): Likewise.
* gnu/packages/wxwidgets.scm (python-wxpython): Likewise.
(python2-wxpython): Likewise.
* gnu/packages/xdisorg.scm (autorandr): Likewise.
* gnu/packages/xorg.scm (hackneyed-x11-cursors): Likewise.
(v86d): Likewise.
(mkfontdir): Likewise.
(xpra): Likewise.

gnu/packages/file-systems.scm

@@ -868,7 +868,8 @@ All of this is accomplished without a centralized metadata server.")
            (lambda* (#:key inputs #:allow-other-keys)
              (substitute* (list "eatmydata.in" "eatmydata.sh.in")
                (("basename|readlink|uname" command)
-                (string-append (assoc-ref inputs "coreutils") "/bin/" command)))))
+                (search-input-file inputs
+                                   (string-append "bin/" command))))))
          (add-before 'patch-file-names 'tighten-symlink-mode
            ;; When the ‘eatmydata’ helper detects that it's a symlink, it will
            ;; transparently invoke the command of the same name.  However, it's
@@ -1046,11 +1047,9 @@ APFS.")
                                              (assoc-ref inputs "bash")
                                              match))
                              (("/bin/(rm|true)" match)
-                              (string-append (assoc-ref inputs "coreutils")
-                                             match))
+                              (search-input-file inputs match))
                              (("/usr(/bin/time)" _ match)
-                              (string-append (assoc-ref inputs "time")
-                                             match))))
+                              (search-input-file inputs match))))
                          (append (find-files "common" ".*")
                                  (find-files "tests" ".*")
                                  (find-files "tools" ".*")
@@ -1097,8 +1096,7 @@ APFS.")
                  (with-output-to-file helper
                    (lambda _
                      (format #t "#!~a --no-auto-compile\n!#\n"
-                             (string-append (assoc-ref inputs "guile")
-                                            "/bin/guile"))
+                             (search-input-file inputs "/bin/guile"))
                      (write
                       `(begin
                          (define (try proc dir)
@@ -1407,8 +1405,9 @@ On Guix System, you will need to invoke the included shell scripts as
              (substitute* '("libfuse/lib/mount_util.c"
                             "libfuse/util/mount_util.c")
                (("/bin/(u?)mount" _ maybe-u)
-                (string-append (assoc-ref inputs "util-linux")
-                               "/bin/" maybe-u "mount")))
+                (search-input-file inputs
+                                   (string-append "bin/" maybe-u
+                                                  "mount"))))
              (substitute* '("libfuse/util/mount.mergerfs.c")
                (("/bin/sh" command)
                 (string-append (assoc-ref inputs "bash-minimal") command))))))))
@@ -1461,10 +1460,9 @@ is similar to mhddfs, unionfs, and aufs.")
                   (string-append "'" (assoc-ref inputs "coreutils") "/bin/rm'")))
                (substitute* "src/mergerfs.mktrash"
                  (("xattr")
-                  (string-append (assoc-ref inputs "python-xattr") "/bin/xattr"))
+                  (search-input-file inputs "/bin/xattr"))
                  (("mkdir")
-                  (string-append (assoc-ref inputs "coreutils") "/bin/mkdir")))
-               #t)))))
+                  (search-input-file inputs "/bin/mkdir"))))))))
       (synopsis "Tools to help manage data in a mergerfs pool")
       (description "mergerfs-tools is a suite of programs that can audit
 permissions and ownership of files and directories on a mergerfs volume,