add #define in struct
Source code:
struct P {
#ifdef HAVE_SOMETHING_AROUND_COMPLICATED
#ifdef HAVE_SOMETHING_INSIDE
double *x;
#endif
#endif
#ifdef HAVE_SOMETHING_ELSE
double *y;
#endif
} *p;
Desired code:
struct P {
#ifdef HAVE_SOMETHING_AROUND_COMPLICATED
#ifdef HAVE_SOMETHING_INSIDE
#define HAVE_P_X
double *x;
#endif
#endif
#ifdef HAVE_SOMETHING_ELSE
#define HAVE_P_Y
double *y;
#endif
} *p;