Emacs: added gnutls variant (tested on Centos 7) (#6711)

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

@@ -43,6 +43,7 @@ class Emacs(AutotoolsPackage):
         values=('gtk', 'athena'),
         description="Select an X toolkit (gtk, athena)"
     )
+    variant('tls', default=False, description="Build Emacs with gnutls")
 
     depends_on('pkgconfig', type='build')
 
@@ -55,6 +56,9 @@ class Emacs(AutotoolsPackage):
     depends_on('libx11', when='+X')
     depends_on('libxaw', when='+X toolkit=athena')
     depends_on('gtkplus+X', when='+X toolkit=gtk')
+    depends_on('gnutls', when='+tls')
+    depends_on('libxpm ^gettext+libunistring', when='+tls')
+    depends_on('ncurses+termlib', when='+tls')
 
     def configure_args(self):
         spec = self.spec