Do not force PGI compiler to use fallback version of lexical_cast (PGI fails tests even in fallback version)

Trialing whitespaces removed

[SVN r78521]

test/implicit_cast.cpp

@@ -28,7 +28,7 @@ int main()
 
     type<foo> f = check_return(boost::implicit_cast<foo>("hello"));
     type<long> z = check_return(boost::implicit_cast<long>(foo("hello")));
-    
+
     // warning supression:
     (void)x;
     (void)f;