diff --git a/clib/clib_sys.c b/clib/clib_sys.c
index 29aeddb..bd336c1 100644
--- a/clib/clib_sys.c
+++ b/clib/clib_sys.c
@@ -16,6 +16,13 @@
  *
  */
 #include "clib_sys.h"
+#ifdef __POSIX_UEFI__
+#    include <uefi.h>
+#elif defined(_WIN32)
+#    include <windows.h>
+#elif defined(__GNUC__) && !defined(__POSIX_UEFI__)
+#    include <unistd.h>
+#endif
 
 /* Interrupt functions. */
 #ifdef __WATCOMC__
@@ -44,6 +51,19 @@ sti()
 }
 #endif
 
+/* Time functions. */
+#ifndef __WATCOMC__
+void
+delay(unsigned int ms)
+{
+#    ifdef _WIN32
+    Sleep(ms);
+#    else
+    usleep(ms * 1000);
+#    endif
+}
+#endif
+
 /* Port I/O functions. */
 #ifdef __WATCOMC__
 /* Defined in header. */
diff --git a/clib/clib_sys.h b/clib/clib_sys.h
index bd25ccd..3a3402b 100644
--- a/clib/clib_sys.h
+++ b/clib/clib_sys.h
@@ -30,6 +30,11 @@ extern void     cli();
 extern void     sti();
 #endif
 
+/* Time functions. */
+#ifndef __WATCOMC__
+extern void     delay(unsigned int ms);
+#endif
+
 /* Port I/O functions. */
 #ifdef __WATCOMC__
 uint8_t inb(uint16_t port);