Command line option for debug flags.

Cython/Compiler/CmdLine.py

@@ -125,9 +125,17 @@ def parse_command_line(args):
                 except ValueError, e:
                     sys.stderr.write("Error in compiler directive: %s\n" % e.args[0])
                     sys.exit(1)
+            elif option.startswith('--debug'):
+                option = option[2:].replace('-', '_')
+                import DebugFlags
+                if option in dir(DebugFlags):
+                    setattr(DebugFlags, option, True)
                 else:
-                sys.stderr.write("Unknown compiler flag: %s\n" % option)
+                    sys.stderr.write("Unknown debug flag: %s\n" % option)
                     bad_usage()
+            else:
+                sys.stderr.write("Unknown compiler flag: %s\n" % option)
+                sys.exit(1)
         else:
             arg = pop_arg()
             if arg.endswith(".pyx"):

Cython/Compiler/DebugFlags.py

+# Can be enabled at the command line with --debug-xxx.
+
 debug_disposal_code = 0
 debug_temp_alloc = 0
 debug_coercion = 0