You don't need the first STRINGIZE2
invocation, as the file name is already a quoted string:
#define STRINGIZE(f,l) f "(" STRINGIZE2(l) "):"
#define STRINGIZE2(x) #x
#define LOCATION_PREFIX STRINGIZE(__FILE__, __LINE__)
int main(){
printf("%s here\n", LOCATION_PREFIX);
printf("%s over here\n", LOCATION_PREFIX);
return 1;
}