podofo: fix library path in pkg-config file

The lib/ directory was being moved to the $lib output post-build without
correcting the path in libpodofo.pc.

pkgs/development/libraries/podofo/0.10.x.nix

@@ -53,10 +53,6 @@ stdenv.mkDerivation (finalAttrs: {
     "-DCMAKE_BUILD_WITH_INSTALL_NAME_DIR=ON"
   ];
 
-  postInstall = ''
-    moveToOutput lib "$lib"
-  '';
-
   meta = {
     homepage = "https://github.com/podofo/podofo";
     description = "A library to work with the PDF file format";

pkgs/development/libraries/podofo/default.nix

@@ -24,8 +24,13 @@ stdenv.mkDerivation rec {
     "-DCMAKE_BUILD_WITH_INSTALL_NAME_DIR=ON"
   ];
 
-  postInstall = ''
-    moveToOutput lib "$lib"
+  postPatch = ''
+    # Use GNU directories to fix multiple outputs
+    failNoMatches='t yes; b no; :yes h; :no p; $ {x; /./{x;q}; q1}'
+    sed -ni src/podofo/CMakeLists.txt \
+        -e 's/LIBDIRNAME/CMAKE_INSTALL_LIBDIR/' -e "$failNoMatches"
+    sed -ni src/podofo/libpodofo.pc.in \
+        -e 's/^libdir=.*/libdir=@CMAKE_INSTALL_LIBDIR@/' -e "$failNoMatches"
   '';
 
   meta = with lib; {