libbacktrace patch committed: OK if zero backward bits

[Ian Lance Taylor]

I've committed this libbacktrace patch to not fail on the case where
there are no bits available when looking backward.  This can happen at
the very end of the frame if no bits are actually required.  The test
case is long and may be proprietary, so not including it.
Bootstrapped and ran libbacktrace and Go testsuite.  Committed to
mainline.

Ian

* elf.c (elf_fetch_bits_backward) Don't fail if no bits are
available.

dda0996e11dbc07f63d3456e36dc5eaec7361004
diff --git a/libbacktrace/elf.c b/libbacktrace/elf.c
index 3cd87020b03..735f8752500 100644
--- a/libbacktrace/elf.c
+++ b/libbacktrace/elf.c
@@ -1182,14 +1182,7 @@ elf_fetch_bits_backward (const unsigned char **ppin,
   val = *pval;
 
   if (unlikely (pin <= pinend))
-    {
-      if (bits == 0)
-       {
-         elf_uncompress_failed ();
-         return 0;
-       }
-      return 1;
-    }
+    return 1;
 
   pin -= 4;