diff --git a/pkgs/tools/networking/network-manager/l2tp.nix b/pkgs/tools/networking/network-manager/l2tp.nix
index a4795a47706f..3cb6034db85d 100644
--- a/pkgs/tools/networking/network-manager/l2tp.nix
+++ b/pkgs/tools/networking/network-manager/l2tp.nix
@@ -32,8 +32,6 @@ stdenv.mkDerivation rec {
   configureFlags =
     if withGnome then "--with-gnome" else "--without-gnome";
 
-  postConfigure = "sed 's/-Werror//g' -i Makefile */Makefile";
-
   meta = with stdenv.lib; {
     description = "L2TP plugin for NetworkManager";
     inherit (networkmanager.meta) platforms;
diff --git a/pkgs/tools/networking/network-manager/openconnect.nix b/pkgs/tools/networking/network-manager/openconnect.nix
index 64b5fb20e892..43eb681be295 100644
--- a/pkgs/tools/networking/network-manager/openconnect.nix
+++ b/pkgs/tools/networking/network-manager/openconnect.nix
@@ -29,15 +29,6 @@ stdenv.mkDerivation rec {
        --replace "/sbin/modprobe" "${kmod}/sbin/modprobe"
   '';
 
-  postConfigure = ''
-     substituteInPlace "./auth-dialog/Makefile" \
-       --replace "-Wstrict-prototypes" "" \
-       --replace "-Werror" ""
-     substituteInPlace "properties/Makefile" \
-       --replace "-Wstrict-prototypes" "" \
-       --replace "-Werror" ""
-  '';
-
   meta = {
     description = "NetworkManager's OpenConnect plugin";
     inherit (networkmanager.meta) maintainers platforms;
diff --git a/pkgs/tools/networking/network-manager/openvpn.nix b/pkgs/tools/networking/network-manager/openvpn.nix
index e6cb346c9288..34e3a3e2959a 100644
--- a/pkgs/tools/networking/network-manager/openvpn.nix
+++ b/pkgs/tools/networking/network-manager/openvpn.nix
@@ -33,15 +33,6 @@ stdenv.mkDerivation rec {
        --replace "/sbin/openvpn" "${openvpn}/sbin/openvpn"
   '';
 
-  postConfigure = ''
-     substituteInPlace "./auth-dialog/Makefile" \
-       --replace "-Wstrict-prototypes" "" \
-       --replace "-Werror" ""
-     substituteInPlace "properties/Makefile" \
-       --replace "-Wstrict-prototypes" "" \
-       --replace "-Werror" ""
-  '';
-
   meta = {
     description = "NetworkManager's OpenVPN plugin";
     inherit (networkmanager.meta) maintainers platforms;
diff --git a/pkgs/tools/networking/network-manager/pptp.nix b/pkgs/tools/networking/network-manager/pptp.nix
index 7b4e0ae4c6ed..a9bee0c74811 100644
--- a/pkgs/tools/networking/network-manager/pptp.nix
+++ b/pkgs/tools/networking/network-manager/pptp.nix
@@ -28,8 +28,6 @@ stdenv.mkDerivation rec {
   configureFlags =
     if withGnome then "--with-gnome --with-gtkver=3" else "--without-gnome";
 
-  postConfigure = "sed 's/-Werror//g' -i Makefile */Makefile";
-
   meta = {
     description = "PPtP plugin for NetworkManager";
     inherit (networkmanager.meta) maintainers platforms;
diff --git a/pkgs/tools/networking/network-manager/vpnc.nix b/pkgs/tools/networking/network-manager/vpnc.nix
index 0275a14bdf4a..97b2001d7592 100644
--- a/pkgs/tools/networking/network-manager/vpnc.nix
+++ b/pkgs/tools/networking/network-manager/vpnc.nix
@@ -30,15 +30,6 @@ stdenv.mkDerivation rec {
        --replace "/sbin/modprobe" "${kmod}/sbin/modprobe"
   '';
 
-  postConfigure = ''
-     substituteInPlace "./auth-dialog/Makefile" \
-       --replace "-Wstrict-prototypes" "" \
-       --replace "-Werror" ""
-     substituteInPlace "properties/Makefile" \
-       --replace "-Wstrict-prototypes" "" \
-       --replace "-Werror" ""
-  '';
-
   meta = {
     description = "NetworkManager's VPNC plugin";
     inherit (networkmanager.meta) maintainers platforms;