svga: add opt to the list of valid build types

For opt build, add VMX86_STATS to the list of cpp defines.

Reviewed-by: Brian Paul <brianp@vmware.com>

common.py

@@ -86,7 +86,7 @@ def AddOptions(opts):
         from SCons.Options.EnumOption import EnumOption
     opts.Add(EnumOption('build', 'build type', 'debug',
                         allowed_values=('debug', 'checked', 'profile',
-                                        'release')))
+                                        'release', 'opt')))
     opts.Add(BoolOption('verbose', 'verbose output', 'no'))
     opts.Add(EnumOption('machine', 'use machine-specific assembly code',
                         default_machine,