add %{...%} block to example in manual

diff --git a/doc/flex.texi b/doc/flex.texi
index 825add31a8edd869eb024a5e1c8f6b09f602a7b5..c7edce69ef7485678636be4a61bcdc25dfd327bc 100644 (file)
--- a/doc/flex.texi
+++ b/doc/flex.texi
@@ -4910,8 +4910,10 @@ custom allocator through @code{yyextra}.
 %option reentrant
 
 /* Initialize the allocator. */
+%{
 #define YY_EXTRA_TYPE  struct allocator*
 #define YY_USER_INIT  yyextra = allocator_create();
+%}
 
 %%
 .|\n   ;