libgcc: i386/linux-unwind.h: always rely on sys/ucontext.h

When gcc is built for x86_64-linux-musl target, stack unwinding from
within signal handler stops at the innermost signal frame.  The reason
for this behaviro is that the signal trampoline is not accompanied with
appropiate CFI directives, and the fallback path in libgcc to recognize
it by the code sequence is only enabled for glibc except 2.0.  The
latter is motivated by the lack of sys/ucontext.h in that glibc version.

Given that all relevant libc-s ship sys/ucontext.h for over a decade,
and that other arches aren't shy of unconditionally using it, follow
suit and remove the preprocessor condition, too.

libgcc/ChangeLog:

	* config/i386/linux-unwind.h: Remove preprocessor
	condition to enable fallback path for all libc-s.

Signed-off-by: Roman Kagan <rkagan@amazon.de>

diff --git a/libgcc/config/i386/linux-unwind.h b/libgcc/config/i386/linux-unwind.h
index fe316ee02cf21b3535a62ce2023fddf8d53e0589..8f37642bbf5587f6d911e07622ae8a2066735713 100644 (file)
--- a/libgcc/config/i386/linux-unwind.h
+++ b/libgcc/config/i386/linux-unwind.h
@@ -33,12 +33,6 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 
 #ifndef inhibit_libc
 
-/* There's no sys/ucontext.h for glibc 2.0, so no
-   signal-turned-exceptions for them.  There's also no configure-run for
-   the target, so we can't check on (e.g.) HAVE_SYS_UCONTEXT_H.  Using the
-   target libc version macro should be enough.  */
-#if defined __GLIBC__ && !(__GLIBC__ == 2 && __GLIBC_MINOR__ == 0)
-
 #include <signal.h>
 #include <sys/ucontext.h>
 
@@ -199,5 +193,4 @@ x86_frob_update_context (struct _Unwind_Context *context,
 }
 
 #endif /* ifdef __x86_64__  */
-#endif /* not glibc 2.0 */
 #endif /* ifdef inhibit_libc  */