old_contents: from spack import *
  
  class Glib(Package):
      """The GLib package contains a low-level libraries useful for
         providing data structure handling for C, portability wrappers
         and interfaces for such runtime functionality as an event loop,
         threads, dynamic loading and an object system."""
      homepage = "https://developer.gnome.org/glib/"
      url      = "http://ftp.gnome.org/pub/gnome/sources/glib/2.42/glib-2.42.1.tar.xz"
  
      version('2.42.1', '89c4119e50e767d3532158605ee9121a')
  
      depends_on("libffi")
      depends_on("zlib")
  
      def install(self, spec, prefix):
          configure("--prefix=%s" % prefix)
          make()
          make("install", parallel=False)
  
new_contents: from spack import *
  import sys
  
  class Glib(Package):
      """The GLib package contains a low-level libraries useful for
         providing data structure handling for C, portability wrappers
         and interfaces for such runtime functionality as an event loop,
         threads, dynamic loading and an object system."""
      homepage = "https://developer.gnome.org/glib/"
      url      = "http://ftp.gnome.org/pub/gnome/sources/glib/2.42/glib-2.42.1.tar.xz"
  
      version('2.42.1', '89c4119e50e767d3532158605ee9121a')
  
      depends_on("libffi")
      depends_on("zlib")
      depends_on("pkg-config")
      depends_on('gettext', sys.platform=='darwin')
  
      def install(self, spec, prefix):
          configure("--prefix=%s" % prefix)
          make()
          make("install", parallel=False)
  
subject: add missing dependencies