vpnc: remove unnecessary patch

We can make the same changes much less invasively using normal Nixpkgs
stuff.  This would make it easier to switch to the actively maintained
fork[1] in future.

The use of $(out)/etc instead of /etc is a bit questionable, but I
don't want to change any behaviour in this patch so I'm leaving it
alone for now.

[1]: https://davidepucci.it/doc/vpnc/

pkgs/tools/networking/vpnc/default.nix

@@ -14,7 +14,7 @@ stdenv.mkDerivation {
     rm -r $sourceRoot/{trunk,branches,tags}
   '';
 
-  patches = [ ./makefile.patch ./no_default_route_when_netmask.patch ];
+  patches = [ ./no_default_route_when_netmask.patch ];
 
   # The `etc/vpnc/vpnc-script' script relies on `which' and on
   # `ifconfig' as found in net-tools (not GNU Inetutils).
@@ -23,6 +23,16 @@ stdenv.mkDerivation {
   nativeBuildInputs = [ makeWrapper ];
   buildInputs = [libgcrypt perl openssl ];
 
+  makeFlags = [
+    "PREFIX=$(out)"
+    "ETCDIR=$(out)/etc/vpnc"
+    "SCRIPT_PATH=$(out)/etc/vpnc/vpnc-script"
+  ];
+
+  postPatch = ''
+    patchShebangs makeman.pl
+  '';
+
   preConfigure = ''
     sed -i 's|^#OPENSSL|OPENSSL|g' Makefile
 

pkgs/tools/networking/vpnc/makefile.patch

@@ -1,22 +0,0 @@
---- vpnc-0.5.1.orig/Makefile	2008-02-10 22:22:43.000000000 +0100
-+++ vpnc-0.5.1/Makefile	2008-02-10 22:22:32.000000000 +0100
-@@ -20,8 +20,8 @@
- # $Id: Makefile 236 2007-09-05 20:40:59Z Joerg Mayer $
- 
- DESTDIR=
--PREFIX=/usr/local
--ETCDIR=/etc/vpnc
-+PREFIX=$(out)
-+ETCDIR=$(out)/etc/vpnc
- BINDIR=$(PREFIX)/bin
- SBINDIR=$(PREFIX)/sbin
- MANDIR=$(PREFIX)/share/man
-@@ -71,7 +71,7 @@
- 	$(CC) -o $@ $^ $(LDFLAGS)
- 
- vpnc.8 : vpnc.8.template makeman.pl vpnc
--	./makeman.pl
-+	perl makeman.pl
- 
- cisco-decrypt : cisco-decrypt.o config.o supp.o sysdep.o vpnc-debug.o
- 	$(CC) -o $@ $^ $(LDFLAGS)