next porting question for gcj

[DJ Delorie]

A simple test will show you:

main()
{
  char *b = alloca(500);
  return b[3];
}

Compile with gcc, and you'll see that alloca is implemented directly,
without function calls.

__builtin_alloca is the internal way gcc implements it; either works
just fine but __builtin_alloca is more immune to being #define'd to
something else.  It's not specific to Cygwin.