Remove unneeded header files from source files throughout. Update copyrights

Remove unneeded header files from source files throughout.  Update copyrights
where appropriate.
* globals.cc: New file for generic global variables.
* mkglobals_h: New file to generate globals.h.
* mkstatic: New Script used to build a (currently non-working) static
libcygwin_s.a.
* Makefile.in: Add unused rule to build a non-working libcygwin_s.a.
(DLL_OFILES): Add globals.o.  Make all objects rely on globals.h.
(globals.h): New target.  Generate globals.h.
* cygtls.h: Honor new CYGTLS_HANDLE define to control when the HANDLE operator
is allowed in _cygtls.
* dcrt0.cc: Move most globals to globals.cc.
* init.cc: Ditto.
* environ.cc (strip_title_path): Remove now-unneeded extern.
* fhandler_serial.cc (fhandler_serial::open): Ditto.
* pinfo.cc: Ditto.
(commune_process): Ditto.
* shared.cc: Ditto.
* glob.cc: Ditto.
* strace.cc: Ditto.
* exceptions.cc: Define CYGTLS_HANDLE before including winsup.h.
* path.cc (stat_suffixes): Move here.
* security.h: Add forward class path_conv declaration.
* smallprint.cc (__small_vsprintf): Make a true c++ function.
(__small_sprintf): Ditto.
(small_printf): Ditto.
(console_printf): Ditto.
(__small_vswprintf): Ditto.
(__small_swprintf): Ditto.
* spawn.cc (spawn_guts): Remove _stdcall decoration in favor of regparm.
(hExeced): Move to globals.cc
* strfuncs.cc (current_codepage): Ditto.
(active_codepage): Ditto.
* sync.cc (lock_process::locker): Move here from dcrt0.cc.
* syscalls.cc (stat_suffixes): Move to path.cc.
* tty.cc (tty::create_master): Uncapitalize fatal warning for consistency.
* winsup.h: Include globals.h to declare most of the grab bag list of globals
which were previously defined here.
* mount.h: Move USER_* defines back to shared_info.h.
* speclib: Force temporary directory cleanup.