Expression evaluator: handle locale setting for decimal separator

NumericEvaluator uses the locale settings to determine the decimal
separator character which will be used when parsing expressions.

common/libeval/numeric_evaluator.cpp

@@ -56,7 +56,8 @@ namespace numEval
 
 NumericEvaluator :: NumericEvaluator() : pClParser(0)
 {
-   cClDecSep = '.';
+   struct lconv* lc = localeconv();
+   cClDecSep = *lc->decimal_point;
 
    bClTextInputStorage = true;