Fix MSVC build: #undef EXPLICIT (which gets defined as 'explicit' somewhere)

Change-Id: I83f6dff2a01d6d7806b2d2f4e6415aee10933e14
diff --git a/basic/source/inc/token.hxx b/basic/source/inc/token.hxx
index 7890ef3..5054bd9 100644
--- a/basic/source/inc/token.hxx
+++ b/basic/source/inc/token.hxx
@@ -28,6 +28,10 @@
#undef SHARED
#endif

#if defined( EXPLICIT )
#undef EXPLICIT
#endif

// The tokenizer is stand-alone, i. e. he can be used from everywhere.
// A BASIC-instance is necessary for error messages. Without BASIC the
// errors are only counted. The BASIC is also necessary when an advanced