Introduce common/common-exceptions.[ch]

This commit moves the exception throwing and catching code
into gdb/common/.  All exception printing code remains in
gdb/exceptions.[ch].

gdb/ChangeLog:

	* common/common-exceptions.h: New file.
	* common/common-exceptions.c: Likewise.
	* Makefile.in (SFILES): Add common/common-exceptions.c.
	(HFILES_NO_SRCDIR): Add common/common-exceptions.h.
	(COMMON_OBS): Add common-exceptions.o.
	(common-exceptions.o): New rule.
	* exceptions.h (common-exceptions.h): Include.
	(gdb_setjmp.h): Do not include.
	(return_reason): Moved to common-exceptions.h.
	(enum return_reason): Likewise.
	(RETURN_MASK): Likewise.
	(typedef return_mask): Likewise.
	(enum errors): Likewise.
	(struct gdb_exception): Likewise.
	(exceptions_state_mc_init): Likewise.
	(exceptions_state_mc_action_iter): Likewise.
	(exceptions_state_mc_action_iter_1): Likewise.
	(TRY_CATCH): Likewise.
	(throw_exception): Likewise.
	(throw_verror): Likewise.
	(throw_vquit): Likewise.
	(throw_error): Likewise.
	(throw_quit): Likewise.
	* exceptions.c (enum catcher_state): Moved to common-exceptions.c.
	(enum catcher_action): Likewise.
	(struct catcher): Likewise.
	(current_catcher): Likewise.
	(catcher_list_size): Likewise.
	(exceptions_state_mc_init): Likewise.
	(catcher_pop): Likewise.
	(exceptions_state_mc): Likewise.
	(exceptions_state_mc_action_iter): Likewise.
	(exceptions_state_mc_action_iter_1): Likewise.
	(throw_exception): Likewise.
	(exception_messages): Likewise.
	(exception_messages_size): Likewise.
	(throw_it): Likewise.
	(throw_verror): Likewise.
	(throw_vquit): Likewise.
	(throw_error): Likewise.
	(throw_quit): Likewise.
	(prepare_to_throw_exception): New function.

gdb/gdbserver/ChangeLog:

	* Makefile.in (SFILES): Add common/common-exceptions.c.
	(OBS): Add common-exceptions.o.
	(common-exceptions.o): New rule.
	* utils.c (prepare_to_throw_exception): New function.

gdb/gdbserver/utils.c

@@ -141,3 +141,11 @@ pfildes (gdb_fildes_t fd)
   return plongest (fd);
 #endif
 }
+
+/* See common/common-exceptions.h.  */
+
+void
+prepare_to_throw_exception (void)
+{
+  /* No client-specific actions required.  */
+}