sha1dc: update from upstream

Update sha1dc from the latest version by the upstream
maintainer[1]. See 07a20f5 ("Makefile: fix unaligned loads in
sha1dc with UBSan", 2019-03-12) for the last update.

This fixes an issue where HP-UX IA64 was wrongly detected as a
Little-endian instead of a Big-endian system, see [2] and [3].

1. cr-marcstevens/sha1collisiondetection@855827c
2. https://public-inbox.org/git/603989bd-f86d-c61d-c6f5-fb6748a65ba9@siemens.com/
3. cr-marcstevens/sha1collisiondetection#50

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: avar

sha1collisiondetection

@@ -93,7 +93,7 @@
 #define SHA1DC_BIGENDIAN
 
 /* Not under GCC-alike or glibc or *BSD or newlib or <processor whitelist> */
-#elif (defined(_AIX))
+#elif (defined(_AIX) || defined(__hpux))
 
 /*
  * Defines Big Endian on a whitelist of OSs that are known to be Big