forks-0.19

Changes for version 0.19

Implemented an exported bless() function allow transparent bless() across threads with forks::shared.
Implemented exported is_thread function in forks::shared.
Implemented custom CHLD signal handler to cleanup zombie process. This change was introduced to resolve an issue on some platforms where using $SIG{CHLD}='IGNORE' resulted in the perl core system() function returning -1 instead of the exit code of the system call. This signal handler is only used if the target system's system() call returns -1 on success when $SIG{CHLD}='IGNORE'.
Added THREADS_SIGCHLD_IGNORE to allow users to force forks to use $SIG{CHLD}='IGNORE' on systems where a custom CHLD signal handler is automatically installed to support correct exit code of perl core system() function.
Added THREADS_NICE env param to allow user to adjust forks.pm server process POSIX::nice value when running as root. If unset, no change is made to the server process priority. This differs from the historical behavior of forks.pm defaulting to nice -19 when run as root.
Patched XS code to be ANSI C86 compliant (again). Code was unintentionally changed to require a minimum of ANSI C89 compliance since 0.17. This should allow all gcc 2.95.x and other C86-compliant compilers to once again build forks.pm.
Fixed prototype mismatch warning when disabling cond_wait when forks is used before forks::shared.
Added patch to quietly ignore sharing an already shared variable. forks::shared used to bombs out in such cases (e.g. $a:shared; share($a);).
Updated to ppport.h 3.06.
Implemented separate package versions for forks and threads. threads package version will represent the most recent threads.pm release that this module is functionally compatible with.
Disabled call to server process on shared variable DESTROY calls to decrease server communication load, as none of the affected TIE classes implement custom DESTROY methods.