diff --git a/components/common/libc/include/stdlib.h b/components/common/libc/include/stdlib.h
index 219a333..b154e2c 100644
--- a/components/common/libc/include/stdlib.h
+++ b/components/common/libc/include/stdlib.h
@@ -18,9 +18,6 @@
 
 #define _ATEXIT_MAX 1
 
-#define isspace(x)    (((x) == ' ') || ((x) == '\r') || ((x) == '\n') || \
-			((x) == '\t') || ((x) == '\b'))
-
 extern void abort(void);
 extern int atexit(void (*func)(void));
 extern void exit(int status);
diff --git a/components/common/libc/src/strtol.c b/components/common/libc/src/strtol.c
index deb862c..d21ef9f 100644
--- a/components/common/libc/src/strtol.c
+++ b/components/common/libc/src/strtol.c
@@ -34,6 +34,7 @@
  * SUCH DAMAGE.
  */
 
+#include <ctype.h>
 #include <errno.h>
 #include <limits.h>
 #include <stddef.h>
diff --git a/components/common/libc/src/strtoll.c b/components/common/libc/src/strtoll.c
index 4e101e8..d8d8f15 100644
--- a/components/common/libc/src/strtoll.c
+++ b/components/common/libc/src/strtoll.c
@@ -34,6 +34,7 @@
  * SUCH DAMAGE.
  */
 
+#include <ctype.h>
 #include <errno.h>
 #include <limits.h>
 #include <stddef.h>
diff --git a/components/common/libc/src/strtoul.c b/components/common/libc/src/strtoul.c
index b42fb14..d6bd820 100644
--- a/components/common/libc/src/strtoul.c
+++ b/components/common/libc/src/strtoul.c
@@ -34,6 +34,7 @@
  * SUCH DAMAGE.
  */
 
+#include <ctype.h>
 #include <errno.h>
 #include <limits.h>
 #include <stddef.h>
diff --git a/components/common/libc/src/strtoull.c b/components/common/libc/src/strtoull.c
index 2e65a43..bd63301 100644
--- a/components/common/libc/src/strtoull.c
+++ b/components/common/libc/src/strtoull.c
@@ -34,6 +34,7 @@
  * SUCH DAMAGE.
  */
 
+#include <ctype.h>
 #include <errno.h>
 #include <limits.h>
 #include <stddef.h>