diff --git a/external/gpl3/gcc/dist/libiberty/sha1.c b/external/gpl3/gcc/dist/libiberty/sha1.c
index 617e743a15e8..e73ebdc2ef28 100644
--- a/external/gpl3/gcc/dist/libiberty/sha1.c
+++ b/external/gpl3/gcc/dist/libiberty/sha1.c
@@ -230,7 +230,11 @@ sha1_process_bytes (const void *buffer, size_t len, struct sha1_ctx *ctx)
   if (len >= 64)
     {
 #if !_STRING_ARCH_unaligned
+# ifdef __clang__
+# define alignof(type) __alignof__(type)
+# else
 # define alignof(type) offsetof (struct { char c; type x; }, x)
+# endif
 # define UNALIGNED_P(p) (((size_t) p) % alignof (sha1_uint32) != 0)
       if (UNALIGNED_P (buffer))
 	while (len > 64)