Clean up TeX support installation, add caveat.

Closes Homebrew/homebrew#42110.

Signed-off-by: Alex Dunn <dunn.alex@gmail.com>

Formula/noweb.rb

@@ -5,38 +5,43 @@ class Noweb < Formula
   homepage 'http://www.cs.tufts.edu/~nr/noweb/'
   url 'ftp://www.eecs.harvard.edu/pub/nr/noweb.tgz'
   version '2.11b'
-  sha1 '3b391c42f46dcb8a002b863fb2e483560a7da51d'
+  sha256 'c913f26c1edb37e331c747619835b4cade000b54e459bb08f4d38899ab690d82'
 
   depends_on 'icon'
 
+  def texpath
+    prefix/'tex/generic/noweb'
+  end
+
   def install
     cd "src" do
       system "bash", "awkname", "awk"
       system "make LIBSRC=icon ICONC=icont CFLAGS='-U_POSIX_C_SOURCE -D_POSIX_C_SOURCE=1'"
 
-      if which 'kpsewhich'
-        ohai 'TeX installation found. Installing TeX support files there might fail if your user does not have permission'
-        texmf = Pathname.new(`kpsewhich -var-value=TEXMFLOCAL`.chomp)
-      else
-        ohai 'No TeX installation found. Installing TeX support files in the noweb Cellar.'
-        texmf = prefix
-      end
-
       bin.mkpath
       lib.mkpath
       man.mkpath
-      (texmf/'tex/generic/noweb').mkpath
+      texpath.mkpath
 
       system "make", "install", "BIN=#{bin}",
                                 "LIB=#{lib}",
                                 "MAN=#{man}",
-                                "TEXINPUTS=#{texmf}/tex/generic/noweb"
+                                "TEXINPUTS=#{texpath}"
       cd "icon" do
         system "make", "install", "BIN=#{bin}",
                                   "LIB=#{lib}",
                                   "MAN=#{man}",
-                                  "TEXINPUTS=#{texmf}/tex/generic/noweb"
+                                  "TEXINPUTS=#{texpath}"
       end
     end
   end
+
+  def caveats; <<-EOS.undent
+    TeX support files are installed in the directory:
+
+      #{texpath}
+
+    You may need to add the directory to TEXINPUTS to run noweb properly.
+    EOS
+  end
 end