diff --git a/modules/arch/x86/x86cpu.gperf b/modules/arch/x86/x86cpu.gperf
index 5878a917..45edd071 100644
--- a/modules/arch/x86/x86cpu.gperf
+++ b/modules/arch/x86/x86cpu.gperf
@@ -27,6 +27,7 @@
 #include <util.h>
 RCSID("$Id$");
 
+#include <ctype.h>
 #include <libyasm.h>
 #include <libyasm/phash.h>
 
diff --git a/modules/arch/x86/x86regtmod.gperf b/modules/arch/x86/x86regtmod.gperf
index e3d0a89e..a5763432 100644
--- a/modules/arch/x86/x86regtmod.gperf
+++ b/modules/arch/x86/x86regtmod.gperf
@@ -27,6 +27,7 @@
 #include <util.h>
 RCSID("$Id$");
 
+#include <ctype.h>
 #include <libyasm.h>
 #include <libyasm/phash.h>