how do I resolve standard libraries?

I am working on a small C program. I am new at this as I am primarily a Java/JS dev.

The program compiles correctly via XCode and using the makefile but in AppCode it shows errors as it doesnt recognize includes for stdio.h, stdlib.h, etc.. How do I configure it to resolve these?

I like the IntelliJ/AppCode UI and editors a lot better than using Sublime+make or XCode/VisualStudio so I hope this is possible. The smallest example that shows this error is

#include <stdio.h>
#include <stdlib.h>

 
#include <time.h>
 

 
int main(int argc, const char * argv[])
{
    printf("Time %4.2f \n", clock());
    return 0;
}