Problems with ## #269

#include <stdio.h>

#define __SAMC21N18A__
#define SAM_PART_IS_DEFINED(part)       (defined(__ ## part ## __))

#define SAM     SAM_PART_IS_DEFINED(SAMC21N18A)


int main()
{
#if SAM
    printf("Hello World");
#endif

    return 0;
}

$ simplecpp mytest.c                                             
                                                                 
                                                                 
                                                                 
                                                                 
                                                                 
                                                                 
                                                                 
                                                                 
int main ( )                                                     
{                                                                
                                                                 
                                                                 
                                                                 
                                                                 
return 0 ;                                                       
}                                                                
mytest.c:1: missing header: Header not found: <stdio.h>