diff --git a/src/x86/intel_minnow_max.c b/src/x86/intel_minnow_max.c
index dab8312..faa9af8 100644
--- a/src/x86/intel_minnow_max.c
+++ b/src/x86/intel_minnow_max.c
@@ -25,6 +25,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <sys/utsname.h>
+#include <ctype.h>
 
 #include "common.h"
 #include "x86/intel_minnow_max.h"
diff --git a/src/x86/x86.c b/src/x86/x86.c
index 55de9d5..ce02e62 100644
--- a/src/x86/x86.c
+++ b/src/x86/x86.c
@@ -23,6 +23,7 @@
  */
 
 #include <stdlib.h>
+#include <string.h>
 
 #include "mraa_internal.h"
 #include "x86/intel_galileo_rev_d.h"