diff --git a/src/parser/lexical.l b/src/parser/lexical.l
index 33a90b9..1025fa0 100644
--- a/src/parser/lexical.l
+++ b/src/parser/lexical.l
@@ -26,7 +26,9 @@ class ObjectBase;
 #include "grammatical.h"
 // Get rid of warning on unused function
 #define YY_NO_INPUT
-// Termination (mostly. in case of errors)
+// struct yyguts_t defined in each flex output file, this emits warning at linking stage
+#define yyguts_t confguts_t
+// Termination (mostly, in case of errors)
 #define yyterminate(ret) { while(0!=YY_CURRENT_BUFFER) yypop_buffer_state(yyscanner); str.erase(); yyextra->retcode=-(ret); return (ret); }
 // Abnormal termination with description of error
 #define yyerrormessage(message,ret) {COUT(ERROR)<<std::endl<<" Lexical error in file "<<yyextra->state.curdir<<yyextra->state.filename<<" at line "<<yyextra->state.curline<<": "<<(message)<<std::endl; yyterminate(ret);}