_Nullable warning on stdio.h on a brand new install of newest commandline tools

Hopefully this is a simple problem...
This is a brand new install of the Xcode 12 command line tools (17 Sept 2020) after an upgrade to Catalina (10.15.6).
I already tried several other fixes which people have posted,
I get 190 warnings on a simple C compile of
Code Block
#include <stdio.h>
#include <stdlib.h>
int main(int argc, char **argv)
{
    printf("FOOOO!\n");
    exit(0);
}

Code Block
...
/Library/Developer/CommandLineTools/SDKs/MacOSX10.15.sdk/usr/include/stdlib.h:356:13: note: insert '_Nonnull' if the pointer should never
      be null
extern char *suboptarg;         /* getsubopt(3) external variable */
            ^
              _Nonnull 
190 warnings generated.

Problem remains with OSX Sequoia, Xcode 16.2 in 2025 but still no response from Apple!

_Nullable warning on stdio.h on a brand new install of newest commandline tools
 
 
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