update BLAKE2_PACKED macro with a non-GCCism fallback

diff --git a/libarchive/archive_blake2.h b/libarchive/archive_blake2.h
index dd6fe6fe5a986dda7ea8cf5c9ab6eac849bbd9e3..8f6b5e9221f4e806b7b367dc6ae4aa448cfc77b2 100644 (file)
--- a/libarchive/archive_blake2.h
+++ b/libarchive/archive_blake2.h
@@ -21,8 +21,10 @@
 
 #if defined(_MSC_VER)
 #define BLAKE2_PACKED(x) __pragma(pack(push, 1)) x __pragma(pack(pop))
-#else
+#elif defined(__GNUC__)
 #define BLAKE2_PACKED(x) x __attribute__((packed))
+#else
+#define BLAKE2_PACKED(x) _Pragma("pack 1") x _Pragma("pack 0")
 #endif
 
 #if defined(__cplusplus)