size_t fread_size = fread(seed, 1, 32, f);
      
    fclose(f);
    if (fread_size == 0) {
        return 1;
    }

As fread was not storing its returned size count into anything and the new compiler warnings flag up an unused variable.  Maybe 

`c if (fread_size != 32) return 1;` ??

not sure how much it should be reading, from the fread documentation:

### Return Value
The total number of elements successfully read is returned.
If this number differs from the count parameter, either a reading error occurred or the end-of-file was reached while reading. In both cases, the proper indicator is set, which can be checked with ferror and feof, respectively.
If either size or count is zero, the function returns zero and both the stream state and the content pointed by ptr remain unchanged.
size_t is an unsigned integral type.