+ avoid misc. warnings
+ * lib/fsusage.c (UNUSED_PARAM): Define.
+ (get_fs_usage): Mark parameter "disk" as unused.
+ * lib/getugroups.c (getgrent): Use "void" in prototype.
+ * lib/mountlist.c: Mark unused parameters.
+ (read_file_system_list): Declare a local with "const".
+ * lib/nanosleep.c (getnow): Declare static.
+ * lib/strftime.c: Include strftime.h, for declaration of nstrftime.
+