Provide correct download urls and additional dependencies.

var/spack/repos/builtin/packages/glib/package.py

@@ -42,10 +42,15 @@ class Glib(Package):
     depends_on('pkg-config', type='build')
     depends_on('gettext', when=sys.platform == 'darwin')
     depends_on('pcre+utf', when='@2.49:')
+    depends_on('gettext', when='@2.49:')
 
     # The following patch is needed for gcc-6.1
     patch('g_date_strftime.patch')
 
+    def url_for_version(self, version):
+        """Handle glib's version-based custom URLs."""
+        return 'http://ftp.gnome.org/pub/gnome/sources/glib/%s/glib-%s.tar.xz' % (version.up_to(2), version)
+
     def install(self, spec, prefix):
         configure("--prefix=%s" % prefix)
         make()