Index: esh-grammar.y
===================================================================
--- esh-grammar.y	(revision 80)
+++ esh-grammar.y	(working copy)
@@ -79,6 +79,9 @@
 /* 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 */
@@ -202,6 +205,7 @@
     }
 
 #define YY_NO_UNPUT
+#define YY_NO_INPUT
 #include "lex.yy.c"
 
 static void
Index: Makefile
===================================================================
--- Makefile	(revision 80)
+++ Makefile	(working copy)
@@ -5,7 +5,7 @@
 LDLIBS=-ll -ldl -lreadline -ltermcap
 # The use of -Wall, -Werror, and -Wmissing-prototypes is mandatory 
 # for this assignment
-CFLAGS=-Wall -Werror -Wmissing-prototypes -g
+CFLAGS=-Wall -Werror -Wmissing-prototypes -g -fPIC
 #YFLAGS=-v
 
 LIB_OBJECTS=list.o esh-utils.o esh-sys-utils.o