Disable following warnings when cross-compiling with a gcc older
  than 3.0, to avoid warnings from third party system headers:

    -Wmissing-prototypes
    -Wunused
    -Wshadow

And on the other hand a message after setsockopt() certainly must use SOCKERRNO.

  Do not enable -pedantic when cross-compiling with a gcc older
  than 3.0, to avoid warnings from third party system headers.

  Highest warning level is double -A, next is single -A.
  Due to the big number of warnings these trigger on third
  party header files it is impratical for us to use any of
  them here. If you want them simply define it in CPPFLAGS.

use the startup of the IPv6 test server as a substitute check for this).

  Warning level reduced from double -A to single -A

_ Update RPG binding accordingly.
_ Fix new options comments.

2) Disable SGI remark: controlling expression is constant

  Due to the HP-UX socklen_t issue it is insane to use the +w1 warning level.
  It generates more than 1100 warnings on socklen_t related statements.

  Until the issue is somehow fixed we will just use the +w2 warning level.

because the struct is declared on the stack and not all members are used so
we could just as well make struct with only struct members we actually need.

for spotting it).

systems supporting getifaddrs(). Also fixed a problem where an IPv6
address could be chosen instead of an IPv4 one for --interface when it
involved a name lookup.

All but the first test cause an infinite loop or other failure and so
are added to DISABLED.

  Disallow run-time dereferencing of null pointers.

  Disable some remarks:

    #4227: padding struct with n bytes to align member.

    #4255: padding size of struct with n bytes to alignment boundary.