bitbake: codegen: implement ast.NodeVisitor.visit_Constant

Since Python 3.8 visit_Num(), visit_Str() and so on are all deprecated
and replaced with visit_Constant.  We can't yet remove the deprecated
functions until we require 3.8, but we can implement visit_Constant to
silence the deprecation warnings.

(Bitbake rev: 97cf0660edd0e2f0df3a5d45b06e566327f90217)

Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/codegen.py

@@ -401,6 +401,12 @@ def visit_Bytes(self, node):
     def visit_Num(self, node):
         self.write(repr(node.n))
 
+    def visit_Constant(self, node):
+        # Python 3.8 deprecated visit_Num(), visit_Str(), visit_Bytes(),
+        # visit_NameConstant() and visit_Ellipsis(). They can be removed once we
+        # require 3.8+.
+        self.write(repr(node.value))
+
     def visit_Tuple(self, node):
         self.write('(')
         idx = -1