Libeval: consistent formatting for NaN

On some platforms like MSVC, NaN prints as "-nan(ind)". This
is a bit needlessly ugly, so print "NaN" on all platforms
consistently.

This fixes a test failure on MSVC.

common/libeval/numeric_evaluator.cpp

@@ -104,8 +104,18 @@ void NUMERIC_EVALUATOR::parseOk()
 
 void NUMERIC_EVALUATOR::parseSetResult( double val )
 {
+    if( std::isnan( val ) )
+    {
+        // Naively printing this with %g produces "nan" on some platforms
+        // and "-nan(ind)" on others (e.g. MSVC). So force a "standard" string.
+        snprintf( m_token.token, m_token.OutLen, "%s", "NaN" );
+    }
+    else
+    {
+        // Can be printed as a floating point
         snprintf( m_token.token, m_token.OutLen, "%.10g", val );
     }
+}
 
 
 wxString NUMERIC_EVALUATOR::OriginalText() const

qa/common/libeval/test_numeric_evaluator.cpp

@@ -117,7 +117,7 @@ static const std::vector<EVAL_CASE> eval_cases_valid = {
     { "1.5", "1.5" },
     { "1,5", "1.5" },
     // Semicolon is valid, but the result is NaN
-    { "1;", "nan" },
+    { "1;", "NaN" },
     // With own unit
     { "1mm", "1" },
     // Unit that's not the evaluator's unit