--- a/CPU.xs
+++ b/CPU.xs
@@ -24,7 +24,6 @@
  #include <winreg.h>
 #else                /* other (try unix) */
  #include <unistd.h>
- #include <sys/unistd.h>
 #endif
 #if defined(__sun) || defined(__sun__)
  #include <sys/processor.h>
