Merged from gcc head revision 146001.

Merged from gcc head revision 146001.
2009-04-13  Ozkan Sezer  <sezeroz@gmail.com>

        PR target/39397
        * pex-common.h (struct pex_obj): Store pid values as pid_t,
        not as long (members *children and (*wait))
        * pex-common.c (pex_run_in_environment): Likewise.
        * pex-win32.c (pex_win32_wait): Return pid_t and properly check
        returned pid value.
        * pex-djgpp.c (pex_djgpp_wait): Return pid_t.
        * pex-msdos.c (pex_msdos_wait): Likewise.