Write literal byte more clearly
diff --git a/library/sha1.c b/library/sha1.c
index c477e9a..604f8ee 100644
--- a/library/sha1.c
+++ b/library/sha1.c
@@ -622,7 +622,7 @@
 
         if( i == 5 || i == 6 )
         {
-            memset( buf, '\xAA', buflen = 80 );
+            memset( buf, 0xAA, buflen = 80 );
             sha1_hmac_starts( &ctx, buf, buflen );
         }
         else