* hppa-tdep.h (hppa_read_pc, hppa_write_pc, hppa_unwind_pc): New

* hppa-tdep.h (hppa_read_pc, hppa_write_pc, hppa_unwind_pc): New
prototypes.
* hppa-tdep.c (hppa_read_pc): Rename from hppa_target_read_pc.
Make global.  Remove HP-UX specific code.  Use
frame_unwind_register_unsigned instead of
frame_unwind_register_signed.
(hppa_write_pc): Rename from hppa_target_write_pc.  Make global.
Remove HP-UX specific code.
(hppa_unwind_pc): Make global.  Remove HP-UX specific code.
(hppa_frame_prev_register_helper): Set "flags" register to zero
for all unwound frames.
(hppa_gdbarch_init): Adjust.
* hppa-hpux-tdep.c (HPPA_HPUX_SS_INSYSCALL): New define.
(hppa_hpux_read_pc, hppa_hpux_write_pc)
(hppa_hpux_unwind_pc): New functions.
(hppa_hpux_init_abi): Set read_pc, write_pc and unwind_pc.