I just made some changes to COMPAT_NETBSD32 and COMPAT_SVR4_32 to handle
   default mapping addresses and limits in a better way.
   
   I have tested the code on amd64. sparc64 is the only other platform
   that uses this code right now. I could only compile-test it. I don't
   expect any more problems, but let me know if there are any.


did COMPAT_SUNOS32 need to change in any way?