sleep: support "inf"

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

coreutils/sleep.c

@@ -68,6 +68,11 @@ int sleep_main(int argc UNUSED_PARAM, char **argv)
 	if (!*argv)
 		bb_show_usage();
 
+	/* GNU sleep accepts "inf", "INF", "infinity" and "INFINITY" */
+	if (strncasecmp(argv[0], "inf", 3) == 0)
+		for (;;)
+			sleep(INT_MAX);
+
 #if ENABLE_FEATURE_FANCY_SLEEP
 # if ENABLE_FLOAT_DURATION
 	/* undo busybox.c setlocale */

miscutils/bc.c

@@ -7407,4 +7407,3 @@ int dc_main(int argc UNUSED_PARAM, char **argv)
 #endif
 
 #endif // DC_BIG
-