scons: Move MSVS_VERSION option to common module.
diff --git a/SConstruct b/SConstruct
index c619804..8880d85 100644
--- a/SConstruct
+++ b/SConstruct
@@ -32,7 +32,6 @@
 
 opts = Variables('config.py')
 common.AddOptions(opts)
-opts.Add(EnumVariable('MSVS_VERSION', 'MS Visual C++ version', None, allowed_values=('7.1', '8.0', '9.0')))
 
 env = Environment(
 	options = opts,
diff --git a/common.py b/common.py
index b7749c9..78e2d0f 100644
--- a/common.py
+++ b/common.py
@@ -91,3 +91,4 @@
 	opts.Add(BoolOption('llvm', 'use LLVM', default_llvm))
 	opts.Add(BoolOption('debug', 'DEPRECATED: debug build', 'yes'))
 	opts.Add(BoolOption('profile', 'DEPRECATED: profile build', 'no'))
+	opts.Add(EnumOption('MSVS_VERSION', 'MS Visual C++ version', None, allowed_values=('7.1', '8.0', '9.0')))