Select precise floating-point model, otherwise doubles are less than 64-bit wide

icc test adjustment:

  Select c89 dialect

  Enable more icc warnings.

  Optimization disabling options used only for icc 9.1

- handles the EINPROGRESS for UDP connects
- uses closesocket instead of close on some paths that were noticed

since these are extremely useful when compiler rejects a set of options.

-s option as well.

to the shell echo command are not interpreted when trying to
remove extra whitespace from shell variable content.

  Disable warnings on structure members padding.

  Remove -b from debug-enabled configuration, as Tiny C might have
  been built without the memory and bounds checker support.

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

    -Wmissing-declarations
    -Wmissing-prototypes
    -Wunused
    -Wshadow

  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

  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.

  Warning level reduced from double -A to single -A

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.

  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.