diff -ruN argtable2-13-orig/src/arg_int.c argtable2-13/src/arg_int.c
--- argtable2-13-orig/src/arg_int.c	2011-01-10 02:44:01.000000000 -0800
+++ argtable2-13/src/arg_int.c	2020-12-19 03:39:18.000000000 -0800
@@ -30,6 +30,7 @@
 
 #include "argtable2.h"
 #include <limits.h>
+#include <ctype.h>
 
 /* local error codes */
 enum {EMINCOUNT=1,EMAXCOUNT,EBADINT,EOVERFLOW};
diff -ruN argtable2-13-orig/tests/fntests.c argtable2-13/tests/fntests.c
--- argtable2-13-orig/tests/fntests.c	2011-01-10 02:44:01.000000000 -0800
+++ argtable2-13/tests/fntests.c	2020-12-19 03:40:18.000000000 -0800
@@ -1,5 +1,6 @@
 #include "../src/argtable2.h"
 #include <assert.h>
+#include <string.h>
 
 /* for memory leak debugging */
 #ifdef DMALLOC
diff -ruN argtable2-13-orig/tests/test_file.c argtable2-13/tests/test_file.c
--- argtable2-13-orig/tests/test_file.c	2011-01-10 02:44:01.000000000 -0800
+++ argtable2-13/tests/test_file.c	2020-12-19 03:40:43.000000000 -0800
@@ -21,6 +21,7 @@
 
 #include "../src/argtable2.h"
 #include <stdlib.h>
+#include <string.h>
 
 /* for memory leak debugging */
 #ifdef DMALLOC