* environ.cc (regopt): Change the first argument to wide char string.

* environ.cc (regopt): Change the first argument to wide char string.
(environ_init): Accommodate change to the first argument of regopt.
* exception.cc (open_stackdumpfile): Accommodate change to the type of progname
in _pinfo.
* external.cc (fillout_pinfo): Ditto.
* fhandler_process.cc (format_process_winexename): Ditto.
(format_process_stat): Ditto.
* fork.cc (fork::parent): Ditto.
* pinfo.cc (pinfo_basic::pinfo_basic): Call GetModuleFileNameW instead of
GetModuleFileName.
(pinfo::thisproc): Accommodate change to the type of progname in _pinfo.
(pinfo_init): Ditto.
* pinfo.h (_pinfo): Change the type of progname to a wide char array.
* registry.h (reg_key::get_int): Change the first argument from constant point
to pointer to constant.
(reg_key::get_string): Ditto.  Change the last argument likewise.
* registry.cc (reg_key::get_int): Accommodate change to the declaration.
(reg_key::get_string): Ditto.
* strace.cc (strace::hello): Accommodate change to the type of progname in
_pinfo.
(strace::vsprntf): Ditto.