m68k-protos.h: Rename m68k_interrupt_function_p to m68k_get_function_kind.

m68k-protos.h: Rename m68k_interrupt_function_p to m68k_get_function_kind.

gcc/
	* config/m68k/m68k-protos.h: Rename m68k_interrupt_function_p
	to m68k_get_function_kind.  Update its prototype.
	* config/m68k/m68k.c (m68k_attribute_table): Add an entry for
	interrupt_thread.
	(m68k_interrupt_function_p): Return enum m68k_function_type
	instead of bool.  Rename to m68k_get_function_kind.
	(m68k_handle_fndecl_attribute): Reject interrupt_thread if the
	target is not fido.
	(m68k_compute_frame_layout): Don't mark any register for save
	if an interrupt_thread attribute is specified.
	(m68k_hard_regno_rename_ok): Update a use of
	m68k_interrupt_function_p.
	* config/m68k/m68k.h (EPILOGUE_USES): Update a use of
	m68k_interrupt_function_p.
	(m68k_function_type): New.
	* config/m68k/m68k.md (*return): Output a 'sleep' instruction
	for a function with an interrupt_thread attribute.
	* doc/extend.texi: Document the interrupt_thread attribute.

gcc/testsuite/
	* gcc.target/m68k/interrupt_thread-1.c,
	gcc.target/m68k/interrupt_thread-2.c,
	gcc.target/m68k/interrupt_thread-3.c: New.
	* gcc.target/m68k/m68k.exp: Accept fido.

From-SVN: r124713