Throughout change TTY_* to PTY_*, tty_* to pty_*, and ttym_* to ptmx_*.

* devices.cc: Regenerate.
* dtable.cc: (fh_alloc): Preserve /dev/tty name when that's what we opened.
(build_fh_pc): Preserve any existing name.
* fhandler.cc (fhandler_base::open_with_arch): Ditto.
* fhandler_tty.cc (fhandler_pty_master::fhandler_pty_master): Force the name to
/dev/ptmx while preserving other pty master device information.
* path.h (cfree_maybe): New macro.
(path_conv::operator =): Free any allocated strings in target.
(path_conv::free_strings): Delete unused function.
* sigproc.cc (proc_terminate): Remove previous accommodation for execed
processes since it didn't have the desired effect.  Change comment to a FIXME.
* spawn.cc (chExeced): Mark NO_COPY.
(exe_suffixes): Ditto.

winsup/cygwin/spawn.cc

@@ -34,7 +34,7 @@ details. */
 #include "winf.h"
 #include "ntdll.h"
 
-static suffix_info exe_suffixes[] =
+static suffix_info NO_COPY exe_suffixes[] =
 {
   suffix_info ("", 1),
   suffix_info (".exe", 1),
@@ -56,7 +56,7 @@ static suffix_info dll_suffixes[] =
 };
 #endif
 
-child_info_spawn *chExeced;
+child_info_spawn NO_COPY *chExeced;
 
 /* Add .exe to PROG if not already present and see if that exists.
    If not, return PROG (converted from posix to win32 rules if necessary).