Fixed spelling of "endianness", and called it "byte ordering" in the
user visible part.
diff --git a/auto/unix b/auto/unix
index 783219e..b0a0e4c 100755
--- a/auto/unix
+++ b/auto/unix
@@ -464,7 +464,7 @@
 
 . auto/types/uintptr_t
 
-. auto/endianess
+. auto/endianness
 
 ngx_type="size_t"; . auto/types/sizeof
 ngx_param=NGX_MAX_SIZE_T_VALUE; ngx_value=$ngx_max_value; . auto/types/value