Win32 WEXITSTATUS too simplistic

win32.h says

/**    Signal stuff*    WIN32 doesn't have wait(), so the return value for children*    is simply the return value
specifiedby the child, without*    any additional information on whether the child terminated*    on its own or via a
signal. These macros are also used*    to interpret the return value of system().*/
 
#define WEXITSTATUS(w)    (w)
#define WIFEXITED(w)    (true)
#define WIFSIGNALED(w)    (false)
#define WTERMSIG(w)        (0)

I think this supposition has been pretty much proven false by recent
reports of silly "exit code" numbers from Win32 users, as for instance
herehttp://archives.postgresql.org/pgsql-bugs/2006-12/msg00163.php
where the postmaster reports server process exited with exit code -1073741819
from what I suspect is really the equivalent of a SIGSEGV trap,
ie, attempted access to already-deallocated memory.  My calculator
says the above is equivalent to hex C0000005, and I say that this
makes it pretty clear that *some* parts of Windows put flag bits into
the process exit code.  Anyone want to run down what we should really
be using instead of the above macros?
        regards, tom lane