Fix euclid for argument of zero

.gitignore

@@ -1,5 +1,5 @@
 
-# Created by https://www.gitignore.io/api/linux,emacs
+# Created by https://www.gitignore.io/api/linux,emacs,commonlisp
 
 ### Linux ###
 *~
@@ -44,3 +44,8 @@ tramp
 
 # cask packages
 .cask/
+
+### CommonLisp ###
+*.FASL
+*.fasl
+*.lisp-temp