neomutt: minor cleanups

- neomutt has changed the binary name so we enable "mutt" via a wrapper script
   with a warning
 - we don't have to manually run the prepare.sh script as autoreconfHook handles
   everything for us
 - doc generation was previously trying to fetch DTDs from the net

pkgs/applications/networking/mailreaders/neomutt/default.nix

@@ -1,7 +1,19 @@
-{ stdenv, fetchFromGitHub, which, autoreconfHook, ncurses, perl
+{ stdenv, fetchFromGitHub, which, autoreconfHook, writeScript, ncurses, perl
 , cyrus_sasl, gss, gpgme, kerberos, libidn, notmuch, openssl, lmdb, libxslt, docbook_xsl, docbook_xml_dtd_42 }:
 
-stdenv.mkDerivation rec {
+let
+  muttWrapper = writeScript "mutt" ''
+    #!${stdenv.shell} -eu
+
+    echo 'The neomutt project has renamed the main binary from `mutt` to `neomutt`.'
+    echo ""
+    echo 'This wrapper is provided for compatibility purposes only. You should start calling `neomutt` instead.'
+    echo ""
+    read -p 'Press any key to launch NeoMutt...' -n1 -s
+    exec neomutt "$@"
+  '';
+
+in stdenv.mkDerivation rec {
   version = "20171013";
   name = "neomutt-${version}";
 
@@ -12,24 +24,35 @@ stdenv.mkDerivation rec {
     sha256 = "0zn8imqfa76bxpkpy111c4vn6vjarbxc8gqv6m18qkksk0ly26l1";
   };
 
-  nativeBuildInputs = [ autoreconfHook docbook_xsl docbook_xml_dtd_42 libxslt.bin which ];
   buildInputs = [
     cyrus_sasl gss gpgme kerberos libidn ncurses
     notmuch openssl perl lmdb
   ];
 
+  nativeBuildInputs = [ autoreconfHook docbook_xsl docbook_xml_dtd_42 libxslt.bin which ];
+
+  enableParallelBuilding = true;
+
+  postPatch = ''
+    for f in doc/*.{xml,xsl}*  ; do
+      substituteInPlace $f \
+        --replace http://docbook.sourceforge.net/release/xsl/current     ${docbook_xsl}/share/xml/docbook-xsl \
+        --replace http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd ${docbook_xml_dtd_42}/xml/dtd/docbook/docbookx.dtd
+    done
+  '';
+
   configureFlags = [
     "--enable-debug"
     "--enable-gpgme"
     "--enable-notmuch"
-    "--with-homespool=mailbox"
-    "--with-gss"
-    "--with-mailpath="
-    "--with-ssl"
-    "--with-sasl"
     "--with-curses"
+    "--with-gss"
+    "--with-homespool=mailbox"
     "--with-idn"
     "--with-lmdb"
+    "--with-mailpath="
+    "--with-sasl"
+    "--with-ssl"
 
     # Look in $PATH at runtime, instead of hardcoding /usr/bin/sendmail
     "ac_cv_path_SENDMAIL=sendmail"
@@ -40,9 +63,9 @@ stdenv.mkDerivation rec {
   # like pgpring, pgpewrap, ...
   NIX_LDFLAGS = "-lidn";
 
-  configureScript = "./prepare";
-
-  enableParallelBuilding = true;
+  postInstall = ''
+    cp ${muttWrapper} $out/bin/mutt
+  '';
 
   meta = with stdenv.lib; {
     description = "A small but very powerful text-based mail client";