remove AC_TYPE_UID_T.  fixed: [ruby-core:04745]

* defines.h: Remove pid_t typedef.

* ruby.h: Define rb_pid_t, rb_gid_t and rb_uid_t in accordance with
 the available system types.

* process.c: Change instances of pid_t and gid_t to their rb_*
 counterparts.

* ext/pty/pty.c: Change pid_t to rb_pid_t.

* vms/config.h: Define HAVE_{P,G,U}ID_T to 1.

* win32/Makefile.sub: Remove #define for {g,u}id_t.

* win32/win32.c: Change pid_t to rb_pid_t.

* wince/Makefile.sub: Remove #define for {g,u}id_t.

* wince/sys/types.h: Remove definitions of {p,g,u}id_t.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_8@8455 b2dd03c8-39d4-4d8f-98ff-823fe69b080e