RFA: Try to include libunwind-ia64.h in libunwind-frame.h

[Tristan Gingold <gingold@adacore.com>]

Hi,

building a cross debugger for ia64 isn't as easy as for most other platforms.
Part of the issue is libunwind.h, which is not well designed for cross operation:

[…]

#ifndef UNW_REMOTE_ONLY

#if defined __arm__
# include "libunwind-arm.h"
#elif defined __hppa__
# include "libunwind-hppa.h"
#elif defined __ia64__
# include "libunwind-ia64.h"
#elif defined __mips__
# include "libunwind-mips.h"
#elif defined __powerpc__ && !defined __powerpc64__
# include "libunwind-ppc32.h"
#elif defined __powerpc64__
# include "libunwind-ppc64.h"
#elif defined __i386__
# include "libunwind-x86.h"
#elif defined __x86_64__
# include "libunwind-x86_64.h"
#else
# error "Unsupported arch"
#endif

[…]

Note that gdb doesn't define UNW_REMOTE_ONLY.  So clearly in my case a wrong header will be used.

I propose to fix this issue with the following patch: it includes libunwind-ia64.h if HAVE_LIBUNWIND_IA64_H is defined.
This is not perfect as libunwind-ia64.h may be detected even if not used, but will work in practice because only ia64 use libunwind.
So maybe it is a little bit over-engineered, and we could simply include libunwind-ia64.h.

(Also, the include of libunwind-ia64.h in ia64-tdep.c isn't necessary.  The reviewer will tell if s/he prefer to keep or remove this include).

Manually tested.

Ok for trunk ?

Tristan.

2012-02-02  Tristan Gingold  <gingold@adacore.com>

	* ia64-tdep.c: Do not include libunwind-ia64.h
	* libunwind-frame.h: Include libunwind-ia64.h instead of
	libunwind.h if possible.

diff --git a/gdb/ia64-tdep.c b/gdb/ia64-tdep.c
index a297ecc..a36dc22 100644
--- a/gdb/ia64-tdep.c
+++ b/gdb/ia64-tdep.c
@@ -43,7 +43,6 @@
 #ifdef HAVE_LIBUNWIND_IA64_H
 #include "elf/ia64.h"           /* for PT_IA_64_UNWIND value */
 #include "libunwind-frame.h"
-#include "libunwind-ia64.h"
 
 /* Note: KERNEL_START is supposed to be an address which is not going
          to ever contain any valid unwind info.  For ia64 linux, the choice
diff --git a/gdb/libunwind-frame.h b/gdb/libunwind-frame.h
index 0251819..932439b 100644
--- a/gdb/libunwind-frame.h
+++ b/gdb/libunwind-frame.h
@@ -29,7 +29,11 @@ struct gdbarch;
 #ifndef LIBUNWIND_FRAME_H
 #define LIBUNWIND_FRAME_H 1
 
+#ifdef HAVE_LIBUNWIND_IA64_H
+#include "libunwind-ia64.h"
+#else
 #include "libunwind.h"
+#endif
 
 struct libunwind_descr
 {