stdio.h: No such file or directory

I got the foll. error compiling a simple ciao.c program

 In file included from ciao.c:1:
/usr/local/lib/gcc/x86_64-apple-darwin18.5.0/8.3.0/include-fixed/stdio.h:78:10: fatal error: _stdio.h: No such file or directory
 #include <stdio.h>
          ^~~~~~~~~~
compilation terminated.

I've already installed Xcode, command line tools and what you want, but nope.

#include <stdio.h>
int main()
{
    printf("Hello, World!");
    return 0;
}

Could you help me please?