[PATCH] Fix ia64 GDB build

[Yao Qi]

Commit 849d0ba8 breaks GDB build for ia64 with --with-libunwind-ia64=yes.
This patch fixes it.

Jason, does it unbreak your build?

gdb:

2018-03-09  Yao Qi  <yao.qi@linaro.org>

	* ia64-libunwind-tdep.c (libunwind_get_reg_special): Change
	parameter type to readable_regcache.
	* ia64-libunwind-tdep.h (libunwind_get_reg_special): Update
	the declaration.
---
 gdb/ia64-libunwind-tdep.c | 2 +-
 gdb/ia64-libunwind-tdep.h | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/gdb/ia64-libunwind-tdep.c b/gdb/ia64-libunwind-tdep.c
index 3ac613c..99782b2 100644
--- a/gdb/ia64-libunwind-tdep.c
+++ b/gdb/ia64-libunwind-tdep.c
@@ -452,7 +452,7 @@ libunwind_sigtramp_frame_sniffer (const struct frame_unwind *self,
    are usually located at BOF, this is not always true and only the libunwind
    info can decipher where they actually are.  */
 int
-libunwind_get_reg_special (struct gdbarch *gdbarch, struct regcache *regcache,
+libunwind_get_reg_special (struct gdbarch *gdbarch, readable_regcache *regcache,
 			   int regnum, void *buf)
 {
   unw_cursor_t cursor;
diff --git a/gdb/ia64-libunwind-tdep.h b/gdb/ia64-libunwind-tdep.h
index 5ac3a28..dc7ec9c 100644
--- a/gdb/ia64-libunwind-tdep.h
+++ b/gdb/ia64-libunwind-tdep.h
@@ -71,7 +71,7 @@ unw_word_t libunwind_find_dyn_list (unw_addr_space_t, unw_dyn_info_t *,
 				    void *);
 
 int libunwind_get_reg_special (struct gdbarch *gdbarch,
-			       struct regcache *regcache,
+			       readable_regcache *regcache,
 			       int regnum, void *buf);
 
 #endif /* IA64_LIBUNWIND_TDEP_H */
-- 
1.9.1