Support for positional-only arguments in @Builtin

Author: otethal

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/Builtin.java

@@ -45,6 +45,8 @@
 
     int maxNumOfPositionalArgs() default -1;
 
+    int numOfPositionalOnlyArgs() default -1;
+
     boolean isGetter() default false;
 
     boolean isSetter() default false;

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/nodes/function/BuiltinFunctionRootNode.java

@@ -240,8 +240,8 @@ private static Signature createSignature(NodeFactory<? extends PythonBuiltinBase
             }
         }
 
-        return new Signature(builtin.takesVarKeywordArgs(), (builtin.takesVarArgs() || builtin.varArgsMarker()) ? parameterNames.length : -1, builtin.varArgsMarker(), parameterNames,
-                        builtin.keywordOnlyNames());
+        return new Signature(builtin.numOfPositionalOnlyArgs(), builtin.takesVarKeywordArgs(), (builtin.takesVarArgs() || builtin.varArgsMarker()) ? parameterNames.length : -1,
+                        builtin.varArgsMarker(), parameterNames, builtin.keywordOnlyNames());
     }
 
     /**