libbb: stop using bb_strtod for now

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

coreutils/sleep.c

@@ -54,11 +54,13 @@ int sleep_main(int argc UNUSED_PARAM, char **argv)
 		char *arg = *argv;
 		if (strchr(arg, '.')) {
 			double d;
+			char *pp;
 			int len = strspn(arg, "0123456789.");
 			char sv = arg[len];
 			arg[len] = '\0';
-			d = bb_strtod(arg, NULL);
-			if (errno)
+			errno = 0;
+			d = strtod(arg, &pp);
+			if (errno || *pp)
 				bb_show_usage();
 			arg[len] = sv;
 			len--;