Added missing dependencies to nauty package (#5348)

* Added missing help2man dependency to nauty

* Add type=build

* Added gmp dependency to nauty package

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

@@ -67,7 +67,9 @@ class Nauty(AutotoolsPackage):
     depends_on('automake',  type='build', when='@2.6r7')
     depends_on('libtool',  type='build', when='@2.6r7')
     depends_on('pkg-config',  type='build')
+    depends_on('help2man', type='build')
     depends_on('zlib')
+    depends_on('gmp')
 
     @property
     def force_autoreconf(self):