Example

#ifdef CONST
#include <header.h>
#endif

#ifdef XPLATOFRM
#include <xplatform.h>
#endif

int main(int argc, char* argv[])
{

return 0;
}


Solution
Avoid putting #include in #ifdef blocks if possible in order to have more portable code.

#include <header.h>

#ifdef XPLATOFRM
//necessary
#include <xplatform.h>
#endif

int main(int argc, char* argv[])
{

return 0;
}