C compiler doesn't generate warning if ternary operator is used for near and based pointers

[jmalak]

Original issue was #1326 (comment).

The test code is

#include <malloc.h>

void *test(int nump)
{
    return( nump ? malloc(5) : __doalloca(5) );
}

if it is compiled with -zu option then it should report message "Pointer truncated" on ternary operator line, but no message is displayed.