declare constant function parameters const (as well as constant function return values)

clients/lcdproc/machine_Linux.c

@@ -15,6 +15,17 @@
 #include <sys/statvfs.h>
 #include <errno.h>
 
+#if TIME_WITH_SYS_TIME
+# include <sys/time.h>
+# include <time.h>
+#else
+# if HAVE_SYS_TIME_H
+#  include <sys/time.h>
+# else
+#  include <time.h>
+# endif
+#endif
+
 #ifdef USE_GETLOADAVG
 # include <sys/loadavg.h>
 #endif