gnu: Add emacs-pdfgrep.

* gnu/packages/emacs-xyz.scm (emacs-pdfgrep): New variable.

Signed-off-by: Nicolas Goaziou <mail@nicolasgoaziou.fr>

gnu/packages/emacs-xyz.scm

@@ -70,7 +70,7 @@
 ;;; Copyright © 2020 Jérémy Korwin-Zmijowski <jeremy@korwin-zmijowski.fr>
 ;;; Copyright © 2020 Alberto Eleuterio Flores Guerrero <barbanegra+guix@posteo.mx>
 ;;; Copyright © 2020 Marius Bakke <mbakke@fastmail.com>
-;;; Copyright © 2020 pinoaffe <pinoaffe@airmail.cc>
+;;; Copyright © 2020, 2022 pinoaffe <pinoaffe@gmail.com>
 ;;; Copyright © 2020, 2021, 2022 Vinicius Monego <monego@posteo.net>
 ;;; Copyright © 2020 Ryan Desfosses <rdes@protonmail.com>
 ;;; Copyright © 2020 Marcin Karpezo <sirmacik@wioo.waw.pl>
@@ -4041,6 +4041,42 @@ DocView mode, and revisiting those PDF files later using the same mode will
 restore the saved place.")
     (license license:gpl3+)))
 
+(define-public emacs-pdfgrep
+  ;; XXX: Upstream does not tag releases.  The commit below matches latest
+  ;; version bump.
+  (let ((commit "e250376d97fc5240e07d81108bbca9b5a9ab50f4"))
+    (package
+      (name "emacs-pdfgrep")
+      (version "1.4")
+      (source
+       (origin
+         (method git-fetch)
+         (uri (git-reference
+               (url "https://github.com/jeremy-compostella/pdfgrep")
+               (commit commit)))
+         (sha256
+          (base32 "17yqvvgkgxmcl8nc0mb9yaz884zcdnz7dwvfi4mxjzp1l05fvwjk"))))
+      (build-system emacs-build-system)
+      (arguments
+       (list #:phases
+             #~(modify-phases %standard-phases
+                 (add-after 'unpack 'patch-pdfgrep-path
+                   (lambda* (#:key inputs #:allow-other-keys)
+                     (make-file-writable "pdfgrep.el")
+                     (emacs-substitute-variables "pdfgrep.el"
+                       ("pdfgrep-program"
+                        (search-input-file inputs "bin/pdfgrep"))))))))
+      (inputs (list pdfgrep))
+      (home-page "https://github.com/jeremy-compostella/pdfgrep")
+      (synopsis "Emacs module providing @code{grep} comparable facilities but
+for PDF files")
+      (description
+       "pdfgrep is a GNU/Emacs module providing @code{grep} comparable
+facilities but for PDF files.  Its usage is similar to the @code{grep}
+function.  For example, using the @code{next-error} function gets you to the
+next matching page.")
+      (license license:gpl3+))))
+
 (define-public emacs-dash
   (package
     (name "emacs-dash")