improve clang support (37)

[Bruno Haible]

clang supports struct members whose type is an enum, with a bitfield width.


2020-08-16  Bruno Haible  <bruno@clisp.org>

        regex: Use space optimization also with clang.
        * lib/regex_internal.h (re_token_t): Use a single byte for the type also
        with clang.

diff --git a/lib/regex_internal.h b/lib/regex_internal.h
index df5303c..dbc503c 100644
--- a/lib/regex_internal.h
+++ b/lib/regex_internal.h
@@ -335,7 +335,7 @@ typedef struct
     Idx idx;                   /* for BACK_REF */
     re_context_type ctx_type;  /* for ANCHOR */
   } opr;
-#if __GNUC__ >= 2 && !defined __STRICT_ANSI__
+#if (__GNUC__ >= 2 || defined __clang__) && !defined __STRICT_ANSI__
   re_token_type_t type : 8;
 #else
   re_token_type_t type;