gcc -E -nostdinc -I./ input.c

grep -vE "(stdio|stdlib).h" code.c > code_.c

#define EXITCODE 0
int main(){
  int i = EOF;
  printf("hellon");
  return EXITCODE;
}

S:c>gcc -E code_.c
# 1 "code_.c"
# 1 "<built-in>"
# 1 "<command-line>"
# 1 "code_.c"

int main(){
  int i = EOF;
  printf("hellon");
  return 0;
}

$ cpphs --nowarn --nomacro -I./ input.c | sed -E 's|#line 1 "missing file: (.*)"|#include <1>|'