(b4_symbol_actions): Don't assume %union was used.

diff --git a/data/c.m4 b/data/c.m4
index a72f059a510137c59f53bca46de60e44c503755f..c651f62c1c012be00e1d1851ab7734b13366bc1a 100644 (file)
--- a/data/c.m4
+++ b/data/c.m4
@@ -327,7 +327,8 @@ m4_define([b4_syncline],
 #                   SYMBOL-ACTION, SYMBOL-TYPENAME)
 # -------------------------------------------------
 m4_define([b4_symbol_actions],
 #                   SYMBOL-ACTION, SYMBOL-TYPENAME)
 # -------------------------------------------------
 m4_define([b4_symbol_actions],

-[m4_pushdef([b4_dollar_dollar], [yyvaluep->$6])dnl
+[m4_pushdef([b4_dollar_dollar],
+   [m4_ifval([$6], [(yyvaluep->$6)], [(*yyvaluep)])])dnl

 m4_pushdef([b4_at_dollar], [(*yylocationp)])dnl
       case $4: /* $3 */
 b4_syncline([$2], [$1])
 m4_pushdef([b4_at_dollar], [(*yylocationp)])dnl
       case $4: /* $3 */
 b4_syncline([$2], [$1])