targhooks.c (default_libcall_value): Don't use LIBCALL_VALUE macro if not defined.
* targhooks.c (default_libcall_value): Don't use LIBCALL_VALUE macro
if not defined. Change type of second argument to const_rtx.
(default_function_value): Call gcc_unreachable if FUNCTION_VALUE
macro not defined.
* targhooks.h (default_libcall_value): Update prototype.
* target.h (struct gcc_target): Change type of second argument of
libcall_value to const_rtx.
* config/arm/arm.c (arm_libcall_value): Change type of second argument
to const_rtx.
(arm_libcall_uses_aapcs_base): Change type of argument to const_rtx.
* doc/tm.texi (TARGET_LIBCALL_VALUE): Revise documentation.