Index: Makefile
===================================================================
RCS file: /home/courses/cs3214/admin/cvs/psh/src-solution/Makefile,v
retrieving revision 1.5
diff -u -r1.5 Makefile
--- Makefile	28 Sep 2011 18:43:45 -0000	1.5
+++ Makefile	2 Dec 2011 02:29:32 -0000
@@ -40,7 +40,7 @@
 esh-grammar.o: esh-grammar.y esh-grammar.l
 	$(LEX) $(LFLAGS) $*.l
 	$(YACC) $(YFLAGS) $<
-	$(CC) -c -o $@ $(CFLAGS) y.tab.c
+	$(CC) -Dlint -c -o $@ $(CFLAGS) y.tab.c
 	rm -f y.tab.c lex.yy.c
 
 # build the shell
Index: esh-grammar.y
===================================================================
RCS file: /home/courses/cs3214/admin/cvs/psh/src-solution/esh-grammar.y,v
retrieving revision 1.4
diff -u -r1.4 esh-grammar.y
--- esh-grammar.y	29 Mar 2011 15:46:28 -0000	1.4
+++ esh-grammar.y	2 Dec 2011 02:29:55 -0000
@@ -81,6 +81,9 @@
 /* Called by parser when command line is complete */
 static void cmdline_complete(struct esh_command_line *);
 
+/* work-around for bug in flex 2.31 and later */
+static void yyunput (int c,char *buf_ptr  ) __attribute__((unused));
+
 %}
 
 /* LALR stack types */
@@ -207,6 +210,7 @@
     }
 
 #define YY_NO_UNPUT
+#define YY_NO_INPUT
 #include "lex.yy.c"
 
 static void