gjs: add profiler support

Necessary to be able to use Sysprof for profiling GJS apps such as GNOME Shell:

105c0a44b1/doc/Profiling.md
https://blogs.gnome.org/chergert/2020/03/15/how-to-use-sysprof-to-part-ii/

pkgs/development/libraries/gjs/default.nix

@@ -12,6 +12,7 @@
 , pango
 , cairo
 , readline
+, libsysprof-capture
 , glib
 , libxml2
 , dbus
@@ -60,6 +61,7 @@ in stdenv.mkDerivation rec {
     gobject-introspection
     cairo
     readline
+    libsysprof-capture
     spidermonkey_91
     dbus # for dbus-run-session
   ];
@@ -73,7 +75,6 @@ in stdenv.mkDerivation rec {
   ];
 
   mesonFlags = [
-    "-Dprofiler=disabled"
     "-Dinstalled_test_prefix=${placeholder "installedTests"}"
   ];