gnu: Add texlive-zref.

* gnu/packages/tex.scm (texlive-zref): New variable.

gnu/packages/tex.scm

@@ -6360,6 +6360,76 @@ Adobe's basic set.")
     ;; No license version specified.
     (license license:gpl3+)))
 
+(define-public texlive-zref
+  (package
+    (inherit (simple-texlive-package
+              "texlive-zref"
+              (list "doc/latex/zref/"
+                    "source/latex/zref/")
+              (base32 "09l2wrqx0navislkx15iazv7jy0ip8bqaw3c0hjf0jy81kqrrm01")))
+    (outputs '("out" "doc"))
+    (arguments
+     (list
+      #:build-targets #~(list "zref.dtx")
+      #:tex-directory "latex/zref"
+      #:phases
+      #~(modify-phases %standard-phases
+          (add-after 'unpack 'chdir
+            (lambda _
+              (setenv "ROOT_DIR" (getcwd))
+              (chdir "source/latex/zref")))
+          (add-after 'install 'install-doc
+            (lambda* (#:key outputs #:allow-other-keys)
+              (define doc (string-append (assoc-ref outputs "doc")
+                                         "/share/texmf-dist/doc"))
+              (mkdir-p doc)
+              (copy-recursively (string-append (getenv "ROOT_DIR") "/doc")
+                                doc))))))
+    (propagated-inputs (list texlive-generic-atbegshi
+                             texlive-generic-gettitlestring
+                             texlive-generic-iftex
+                             texlive-latex-atveryend
+                             texlive-latex-kvoptions
+                             texlive-latex-pdftexcmds
+                             texlive-latex-xkeyval))
+    (home-page "https://github.com/ho-tex/zref")
+    (synopsis "Reference scheme for LaTeX")
+    (description "This package offers a means to remove the limitation, of
+only two properties, that is inherent in the way LaTeX's reference system
+works.  The package implements an extensible referencing system, where
+properties may be defined and used in the course of a document.  It provides
+an interface for macro programmers to access the new reference scheme and some
+modules that use it.  Modules available are:
+@table @code
+@item zref-user
+use zref for traditional labels and references;
+@item zref-abspage
+retrieve absolute page numbers (physical pages, as opposed to the logical page
+number that is normally typeset when a page number is requested;
+@item zref-lastpage
+provide a zref-label for the last page of the document;
+@item zref-nextpage
+provide the page number of the next page of the document;
+@item zref-totpages
+provide the total number of pages in the document;
+@item zref-pagelayout
+provide the page layout parameters of a each page (which may then be printed
+at the end of the document);
+@item zref-perpage
+make a counter reset for each new page;
+@item zref-titleref
+make section title or caption text available through the reference system;
+@item zref-savepos
+make positions on a page available;
+@item zref-dotfill
+controlled dot-filling
+@item zref-env
+record the latest environment's name and the line it started on;
+@item zref-xr
+provide the facilities of the xr and xr-hyper packages.
+@end table")
+    (license license:lppl1.3c+)))
+
 (define-deprecated-package texlive-fonts-adobe-zapfding texlive-zapfding)
 
 (define-public texlive-fonts-rsfs