syscall: code shrink

text    data     bss     dec     hex filename
 777209     974    9676  787859   c0593 busybox_old
 777042     974    9676  787692   c04ec busybox_unstripped

libbb/trim.c

@@ -16,12 +16,16 @@ void trim(char *s)
 	size_t lws;
 
 	/* trim trailing whitespace */
-	while (len && isspace(s[len-1])) --len;
+	while (len && isspace(s[len-1]))
+		--len;
 
 	/* trim leading whitespace */
 	if (len) {
 		lws = strspn(s, " \n\r\t\v");
-		memmove(s, s + lws, len -= lws);
+		if (lws) {
+			len -= lws;
+			memmove(s, s + lws, len);
+		}
 	}
 	s[len] = '\0';
 }