gnu: Add texlive-helvetic.

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

gnu/packages/tex.scm

@@ -1319,6 +1319,32 @@ described in the TeXbook, together with various supporting files (some also
 discussed in the book).")
     (license license:knuth)))
 
+(define-public texlive-helvetic
+  (package
+    (inherit (simple-texlive-package
+              "texlive-helvetic"
+              (list "/dvips/helvetic/"
+                    "/fonts/afm/adobe/helvetic/"
+                    "/fonts/afm/urw/helvetic/"
+                    "/fonts/map/dvips/helvetic/"
+                    "/fonts/tfm/adobe/helvetic/"
+                    "/fonts/tfm/monotype/helvetic/"
+                    "/fonts/tfm/urw35vf/helvetic/"
+                    "/fonts/type1/urw/helvetic/"
+                    "/fonts/vf/adobe/helvetic/"
+                    "/fonts/vf/monotype/helvetic/"
+                    "/fonts/vf/urw35vf/helvetic/"
+                    "/tex/latex/helvetic/")
+              (base32
+               "0c3f1ly7y6404z0akbfbbfql13sz717v0n0g69qjpr69hi4n0nsl")
+              #:trivial? #t))
+    (home-page "https://ctan.org/pkg/urw-base35")
+    (synopsis "URW Base 35 font pack for LaTeX")
+    (description "This package provides a drop-in replacements for the Helvetica
+font from Adobe's basic set.")
+    ;; No license version specified.
+    (license license:gpl3+)))
+
 (define-public texlive-hyphen-afrikaans
   (package
     (inherit (texlive-hyphen-package