network-manager/l2tp: replace patch by substitutions to simplify upgrades

pkgs/tools/networking/network-manager/l2tp-purity.patch

···
-diff --git a/src/nm-l2tp-service.c b/src/nm-l2tp-service.c
-index d2c9dc4..e61d3d2 100644
---- a/src/nm-l2tp-service.c
-+++ b/src/nm-l2tp-service.c
-@@ -655,9 +655,7 @@ nm_find_ipsec (void)
- {
- 	static const char *ipsec_binary_paths[] =
- 		{
--			"/sbin/ipsec",
--			"/usr/sbin/ipsec",
--			"/usr/local/sbin/ipsec",
-+                        "@strongswan@/bin/ipsec",
- 			NULL
- 		};
- 
-@@ -677,9 +675,7 @@ nm_find_l2tpd (void)
- {
- 	static const char *l2tp_binary_paths[] =
- 		{
--			"/sbin/xl2tpd",
--			"/usr/sbin/xl2tpd",
--			"/usr/local/sbin/xl2tpd",
-+                        "@xl2tpd@/bin/xl2tpd",
- 			NULL
- 		};
- 

pkgs/tools/networking/network-manager/l2tp.nix

···
-{ stdenv, fetchFromGitHub, substituteAll, automake, autoconf, libtool, intltool, pkgconfig
+{ stdenv, fetchFromGitHub, automake, autoconf, libtool, intltool, pkgconfig
 , networkmanager, ppp, xl2tpd, strongswan
 , withGnome ? true, gnome3 }:
 
···
   version = "0.9.8.7";
 
   src = fetchFromGitHub {
-    owner = "seriyps";
-    repo = "NetworkManager-l2tp";
-    rev = version;
+    owner  = "seriyps";
+    repo   = "NetworkManager-l2tp";
+    rev    = version;
     sha256 = "07gl562p3f6l2wn64f3vvz1ygp3hsfhiwh4sn04c3fahfdys69zx";
   };
 
···
 
   nativeBuildInputs = [ automake autoconf libtool intltool pkgconfig ];
 
-  configureScript = "./autogen.sh";
+  postPatch = ''
+    sed -i -e 's%"\(/usr/sbin\|/usr/pkg/sbin\|/usr/local/sbin\)/[^"]*",%%g' ./src/nm-l2tp-service.c
+
+    substituteInPlace ./src/nm-l2tp-service.c \
+      --replace /sbin/ipsec  ${strongswan}/bin/ipsec \
+      --replace /sbin/xl2tpd ${xl2tpd}/bin/xl2tpd
+
+    # Workaround https://github.com/xelerance/xl2tpd/issues/108
+    substituteInPlace ./src/nm-l2tp-service.c --replace 'write_config_option (pppopt_fd, "lock\n");' ""
+  '';
+
+  preConfigure = "./autogen.sh";
 
   configureFlags =
     if withGnome then "--with-gnome" else "--without-gnome";
 
   postConfigure = "sed 's/-Werror//g' -i Makefile */Makefile";
 
-  patches =
-    [ ( substituteAll {
-        src = ./l2tp-purity.patch;
-        inherit xl2tpd strongswan;
-      })
-    ];
-
-  # Workaround https://github.com/xelerance/xl2tpd/issues/108
-  postPatch = ''
-    substituteInPlace ./src/nm-l2tp-service.c --replace 'write_config_option (pppopt_fd, "lock\n");' ""
-  '';
-
   meta = with stdenv.lib; {
     description = "L2TP plugin for NetworkManager";
     inherit (networkmanager.meta) platforms;
     homepage = https://github.com/seriyps/NetworkManager-l2tp;
     license = licenses.gpl2;
-    maintainers = with maintainers; [ abbradar ];
+    maintainers = with maintainers; [ abbradar obadz ];
   };
 }