n_1:    Trigraph sequences.             
n_2:    Line splicing by <backslash>.   
n_3:    Handling of comment.            
n_4:    Tokens spelled by digraphs.     
n_5:    Spaces or tabs in pp-directive. 
n_6:    #include directive.             
n_7:    #line directive.                
n_9:    #pragma directive.              
n_10:   #if, #elif pp-directive.        
n_11:   Operator "defined" in #if.      
n_12:   Pp-number and type of #if expr. 
n_13:   Valid operators in #if expr.    
n_13.5: Usual arithmetic conversion.    
n_13.7: Short-circuit evaluation of #if.
n_13.8: Grouping of #if sub-expressions.
n_13.13:    #if expression with macros. 
n_15:   #ifdef, #ifndef directives.     
n_18:   #define directive.              
n_19:   Valid re-definitions of macros. 
n_20:   Macro name identical to keyword.
n_21:   Tokenization (no token merging).
n_22:   Tokenization of pp-number.      
n_23:   ## operator in macro definition.
n_24:   # operator in macro definition. 
n_25:   Pre-expansion of macro args.    
n_26:   No recursive replacement.       
n_27:   Rescanning of a macro.          
n_28:   Standard pre-defined macros.    
n_29:   #undef directive.               
n_30:   Macro call crossing lines.      
n_32:   Escape sequence in char-const.  
n_37:   Translation limits.             
i_32.3: Character constant in #if.      
i_35:   Multi-character character const.
i_35.3: Multi-character wide character. 

Total number of tests unpassed.