Big Endian Detection: Add a whitelist of always BE OSs

Hopefully fix the issue with AIX falling through this detection logic and being detected as Little Endian reported on the Git mailing list, see https://public-inbox.org/git/[email protected]/ Attempt to solve this by extending the existing fallback we have for detecting always Big Endian processors to also detecting always Big Endian OSs. See the public-inbox link in the comment I'm adding for why this should work. I have not tested this myself, since I have no access to AIX. I'll be pointing Michael Felt to the relevant MR so he can test it before this is merged.

Author: avar

lib/sha1.c

@@ -93,13 +93,23 @@
 #defineSHA1DC_BIGENDIAN
 
 /* Not under GCC-alike or glibc or *BSD or newlib or <processor whitelist> */
+#elif (defined(_AIX))
+
+/*
+ * Defines Big Endian on a whitelist of OSs that are known to be Big
+ * Endian-only. See
+ * https://public-inbox.org/git/[email protected]/
+ */
+#defineSHA1DC_BIGENDIAN
+
+/* Not under GCC-alike or glibc or *BSD or newlib or <processor whitelist> or <os whitelist> */
 #elif defined(SHA1DC_ON_INTEL_LIKE_PROCESSOR)
 /*
  * As a last resort before we do anything else we're not 100% sure
  * about below, we blacklist specific processors here. We could add
  * more, see e.g. https://wiki.debian.org/ArchitectureSpecificsMemo
  */
-#else/* Not under GCC-alike or glibc or *BSD or newlib or <processor whitelist> or <processor blacklist> */
+#else/* Not under GCC-alike or glibc or *BSD or newlib or <processor whitelist> or <os whitelist> or <processor blacklist> */
 
 /* We do nothing more here for now */
 /*#error "Uncomment this to see if you fall through all the detection"*/