treewide: remove placeholder usage

Temporary compatibility fix, continuation of https://github.com/NixOS/nixpkgs/pull/37860

pkgs/desktops/gnome-3/core/evolution-data-server/default.nix

@@ -32,6 +32,9 @@ stdenv.mkDerivation rec {
     "-DCMAKE_SKIP_BUILD_RPATH=OFF"
   ];
 
+  postPatch = ''
+    cmakeFlags="-DINCLUDE_INSTALL_DIR=$dev/include $cmakeFlags"
+  '';
 
   preFixup = ''
     for f in $(find $out/libexec/ -type f -executable); do

pkgs/development/libraries/pipewire/default.nix

@@ -34,7 +34,7 @@ in stdenv.mkDerivation rec {
     "-Denable_gstreamer=true"
   ];
 
-  PKG_CONFIG_SYSTEMD_SYSTEMDUSERUNITDIR = "${placeholder "out"}/lib/systemd/user";
+  PKG_CONFIG_SYSTEMD_SYSTEMDUSERUNITDIR = "lib/systemd/user";
 
   FONTCONFIG_FILE = fontsConf; # Fontconfig error: Cannot load default config file
 

pkgs/os-specific/linux/selinux-sandbox/default.nix

@@ -26,7 +26,7 @@ stdenv.mkDerivation rec {
     substituteInPlace Makefile --replace "-m 4755" "-m 755"
     substituteInPlace sandboxX.sh \
       --replace "#!/bin/sh" "#!${bash}/bin/sh" \
-      --replace "/usr/share/sandbox/start" "${placeholder "out"}/share/sandbox/start" \
+      --replace "/usr/share/sandbox/start" "$out/share/sandbox/start" \
       --replace "/usr/bin/cut" "${coreutils}/bin/cut" \
       --replace "/usr/bin/Xephyr" "${xorgserver}/bin/Xepyhr" \
       --replace "secon" "${policycoreutils}/bin/secon"