(struct gdbarch_tdep): Add struct_return member.
* arm-tdep.c (arm_return_value): Return
RETURN_VALUE_STRUCT_CONVENTION for aggregates when the ABI uses
pcc_struct_return.
(arm_gdbarch_init): Default to reg_struct_return.
* armobsd-tdep.c (armobsd_init_abi): Set pcc_struct_return.
* Makefile.in (ALLDEPFILES): Add armobsd-tdep.c.
(armobsd-tdep.o): New dependency.
* config/arm/obsd.mt: New file.
* configure.tgt: (arm*-*-openbsd*): Set gdb_target to obsd.