libc: remove C++ comments from public headers.

Change-Id: I4af84f912062cd2ff34711c25122fb323f20c032
diff --git a/libc/include/sys/file.h b/libc/include/sys/file.h
index 06937ff..cf2f4b1 100644
--- a/libc/include/sys/file.h
+++ b/libc/include/sys/file.h
@@ -31,7 +31,7 @@
 #include <sys/cdefs.h>
 #include <sys/types.h>
 
-// ANDROID: needed for flock()
+/* ANDROID: needed for flock() */
 #include <unistd.h>
 #include <fcntl.h>