diff --git a/cd.nix b/cd.nix
index 3125925..6f1a352 100644
--- a/cd.nix
+++ b/cd.nix
@@ -2,7 +2,7 @@
 , fetchurl
 , lsb-release
 , pkg-config
-, gtk2
+, gtk3
 , im
 , libGLU
 , ftgl
@@ -25,7 +25,7 @@ stdenv.mkDerivation rec {
   ];
   
   buildInputs = [
-    gtk2
+    gtk3
     libGLU
     ftgl
     lua51Packages.lua
@@ -34,14 +34,20 @@ stdenv.mkDerivation rec {
   propagatedBuildInputs = [
     im
   ];
-  
+
+  # The PDF support relies on a proprietary paid-for library.
   postPatch = ''
-    patchShebangs .
     sed -i 's/\bcdpdf\b//g' src/Makefile
     sed -i 's/\bcdluapdf5\b//g' src/Makefile
   '';
 
-  makeFlags = [ "NO_DEPEND=Yes" "USE_PKGCONFIG=Yes" ];
+  makeFlags = [
+    "NO_DEPEND=Yes"
+    "USE_PKGCONFIG=Yes"
+    "USE_GTK3=Yes"
+    "GTK_DEFAULT=Yes"
+  ];
+  
   NIX_CFLAGS_COMPILE = ''
     -Wno-implicit-function-declaration
     -Wno-incompatible-pointer-types
@@ -58,7 +64,7 @@ Description: A vector graphics toolkit with device independent output
 Version: ${version}
 Libs: -L${placeholder "out"}/lib -lcd
 Cflags: -I${placeholder "out"}/include
-Requires: im gtk+-2.0 glu ftgl
+Requires: im gtk+-3.0 glu ftgl
 '';
   
   installPhase = ''
diff --git a/im.nix b/im.nix
index 9f74393..3eaeb35 100644
--- a/im.nix
+++ b/im.nix
@@ -46,7 +46,6 @@ Requires: fftw3 libpng zlib
 '';
   
   postPatch = ''
-    patchShebangs .
     sed -i '1i#include <unistd.h>' src/libjasper2/base/jas_stream.c
   '';
 
diff --git a/iup.nix b/iup.nix
index 6c74771..1ba7050 100644
--- a/iup.nix
+++ b/iup.nix
@@ -3,7 +3,9 @@
 , fetchurl
 , lsb-release
 , pkg-config
-, gtk2
+, gtk3
+, webkitgtk_4_1
+, libsoup_3
 , im
 , libGLU
 , ftgl
@@ -27,7 +29,9 @@ stdenv.mkDerivation rec {
   
   buildInputs = [
     ftgl
-    gtk2
+    gtk3
+    webkitgtk_4_1
+    libsoup_3
     libGLU
     lua51Packages.lua
   ];
@@ -38,24 +42,21 @@ stdenv.mkDerivation rec {
   ];
 
   postPatch = ''
-    patchShebangs .
     sed -i 's/\biupweb\b//g' Makefile
     sed -i 's/\biupvled\b//g' Makefile
 
     sed -i 's/\biupluaweb\b//g' srclua5/Makefile
     substituteInPlace srclua5/config.mak \
       --replace-fail "NO_LUALINK = Yes" "NO_LUALINK ="
-
-    # Since IUP doesn't provide it, supply pkg-config file.
   '';
   
   makeFlags = [
     "NO_DEPEND=Yes"
     "USE_PKGCONFIG=Yes"
-    "USE_GTK2=Yes"
+    "USE_GTK3=Yes"
     "GTK_DEFAULT=Yes"
     "LUA_SFX="
-
+    
     "CD_LIB=${cd}/lib"
     "IM_LIB=${im}/lib"
     "LUA_LIB=${lua51Packages.lua}/lib"
@@ -78,7 +79,7 @@ Description: A portable toolkit for building graphical user interfaces
 Version: ${version}
 Libs: -L${placeholder "out"}/lib -liup
 Cflags: -I${placeholder "out"}/include
-Requires: cd im gtk+-2.0 glu ftgl
+Requires: cd im gtk+-3.0 glu ftgl
 '';
   
   installPhase = ''