libbacktrace patch committed: don't skip aligned byte

[Ian Lance Taylor via Gcc-patches]

This libbacktrace patch by Rui Ueyama fixes handling an uncompressed
block that starts at an aligned byte.  If the bits before the
uncompressed block ended at a byte boundary, libbacktrace accidentally
skipped the next byte, which is the first byte of the length of the
block.  Bootstrapped and ran libbacktrace tests on
x86_64-pc-linux-gnu.  Committed to mainline.

Ian

            * elf.c (elf_zlib_inflate): Don't skip initial aligned byte in
            uncompressed block.

584ae0f0eea2a162dc02984c5976d5cbab5cd1e7
diff --git a/libbacktrace/elf.c b/libbacktrace/elf.c
index 5c7c21a8da7..8b82dd45875 100644
--- a/libbacktrace/elf.c
+++ b/libbacktrace/elf.c
@@ -1796,7 +1796,7 @@ elf_zlib_inflate (const unsigned char *pin, size_t sin, 
uint16_t *zdebug_table,
              /* An uncompressed block.  */
 
              /* If we've read ahead more than a byte, back up.  */
-             while (bits > 8)
+             while (bits >= 8)
                {
                  --pin;
                  bits -= 8;