gnu: mit-scheme: Use minimal texlive-union.

* gnu/packages/scheme.scm (mit-scheme)[native-inputs]: Replace texlive with texlive-union.

gnu/packages/scheme.scm

@@ -105,6 +105,10 @@
                                (find-files "src/compiler" "^make\\.")))
              (chdir "src")
              #t))
+         ;; FIXME: the texlive-union insists on regenerating fonts.  It stores
+         ;; them in HOME, so it needs to be writeable.
+         (add-before 'build 'set-HOME
+           (lambda _ (setenv "HOME" "/tmp") #t))
          (replace 'build
            (lambda* (#:key system outputs #:allow-other-keys)
              (let ((out (assoc-ref outputs "out")))
@@ -151,7 +155,7 @@
                (delete-file-recursively old-doc-dir)
                #t))))))
     (native-inputs
-     `(("texlive" ,texlive)
+     `(("texlive" ,(texlive-union (list texlive-tex-texinfo)))
        ("texinfo" ,texinfo)
        ("m4" ,m4)))
     (inputs