@@ -21,11 +21,14 @@
 #ifdef __GLIBC__
 # undef __USE_XOPEN
 #endif
 
 #include <errno.h>
-#include <unistd.h>
+
+#ifdef HAVE_UNISTD_H
+# include <unistd.h>
+#endif
 
 #ifdef HAVE_SYS_IOCTL_H
 # include <sys/ioctl.h>
 #endif
 #ifdef HAVE_SYS_TTYCOM_H