msvc-inval: Install handler globally.

msvc-inval: Install handler globally.

* lib/msvc-inval.h (STATUS_GNULIB_INVALID_PARAMETER): Define also for
!_MSC_VER.
(gl_msvc_invalid_parameter_handler): Remove declaration.
(gl_msvc_inval_restart_valid, gl_msvc_inval_ensure_handler): New
declarations.
(TRY_MSVC_INVAL, CATCH_MSVC_INVAL, DONE_MSVC_INVAL) [!_MSC_VER]:
Install the handler globally, don't uninstall it.
* lib/msvc-inval.c (gl_msvc_inval_restart_valid): New variable.
(gl_msvc_invalid_parameter_handler): Make static. If the restart is not
currently valid, call RaiseException instead.
(gl_msvc_inval_initialized, gl_msvc_inval_ensure_handler): Define also
for !_MSC_VER.