libc: remove C++ comments from public headers.

Change-Id: I4af84f912062cd2ff34711c25122fb323f20c032
diff --git a/libc/include/sys/ioctl_compat.h b/libc/include/sys/ioctl_compat.h
index d79b67a..cab5c80 100644
--- a/libc/include/sys/ioctl_compat.h
+++ b/libc/include/sys/ioctl_compat.h
@@ -39,8 +39,8 @@
 #ifndef _SYS_IOCTL_COMPAT_H_
 #define	_SYS_IOCTL_COMPAT_H_
 
-//#include <sys/ttychars.h>
-//#include <sys/ttydev.h>
+/*#include <sys/ttychars.h>*/
+/*#include <sys/ttydev.h>*/
 
 struct tchars {
 	char	t_intrc;	/* interrupt */