Use casts to work around bug in Android TEMP_FAILURE_RETRY macro

Use casts to work around bug in Android TEMP_FAILURE_RETRY macro

See http://code.google.com/p/android/issues/detail?id=37426
"unistd.h TEMP_FAILURE_RETRY generates warning when used with syscall
 that returns unsigned int".

The Android version of this macro will generate a signed/unsigned
comparison when used with a syscall function that returns an unsigned
value such as inet_addr(), which returns in_addr_t, which is defined as
an unsigned int. By casting the result to an int before the macro
processes it, and then casting it back to an in_addr_t after the macro
returns it we are able to avoid the signed/unsigned comparison, and so
avoid the signed/unsigned comparison warning.

Committed: https://code.google.com/p/dart/source/detail?r=12395

[jackpal, 2012-09-14 00:54:51]

Guessing iposva would be interested in reviewing (from git blame of
runtime/bin/socket_linux.cc .)

Please let me know if someone else should review.

[Ivan Posva, 2012-09-14 08:06:58]

cc: ager

LGTM -ip