gnu: texlive-optex: Use LuaHBTeX instead of LuaTeX.

* gnu/packages/tex.scm (texlive-optex)[arguments]<#:phases>{symlink-binaries}:
Symlink luahbtex binary instead of luatex.

Change-Id: I5e326b9b9205f6f6fd652f6dcbf7914060a248b0
Signed-off-by: Nicolas Goaziou <mail@nicolasgoaziou.fr>

gnu/packages/tex.scm

@@ -77993,11 +77993,11 @@ and back-ends.  It also ensures compatibility with the @code{media9} and
            #~(modify-phases %standard-phases
                (add-after 'install 'symlink-binaries
                  (lambda* (#:key inputs #:allow-other-keys)
-                   (let ((luatex (search-input-file inputs "bin/luatex"))
+                   (let ((luahbtex (search-input-file inputs "bin/luahbtex"))
                          (bin (string-append #$output "/bin")))
                      (mkdir-p bin)
                      (with-directory-excursion bin
-                       (symlink luatex "optex"))))))))
+                       (symlink luahbtex "optex"))))))))
     (native-inputs (list (if (target-64bit?) libfaketime datefudge)))
     (propagated-inputs
      (list texlive-amsfonts