treewide: De-inline uses of lib.boolToString

This commit should not change eval results

pkgs/development/libraries/gdk-pixbuf/default.nix

@@ -21,6 +21,7 @@
 , doCheck ? false
 , makeWrapper
 , fetchpatch
+, lib
 }:
 
 stdenv.mkDerivation rec {
@@ -74,7 +75,7 @@ stdenv.mkDerivation rec {
   mesonFlags = [
     "-Ddocs=true"
     "-Dx11=false" # use gdk-pixbuf-xlib
-    "-Dgir=${if gobject-introspection != null then "true" else "false"}"
+    "-Dgir=${lib.boolToString (gobject-introspection != null)}"
     "-Dgio_sniffing=false"
   ];