diff --git a/runtime.c b/runtime.c
index c0d0e69d..7d665df4 100644
--- a/runtime.c
+++ b/runtime.c
@@ -51,6 +51,7 @@ int gc_num_ans;
 jmp_buf jmp_main; /* Where to jump to. */
 
 object Cyc_global_variables = nil;
+object Cyc_command_line_arguments = nil;
 
 static symbol_type __EOF = {eof_tag, "", nil}; // symbol_type in lieu of custom type
 const object Cyc_EOF = &__EOF;
diff --git a/runtime.h b/runtime.h
index 688d6acc..19fd15a5 100644
--- a/runtime.h
+++ b/runtime.h
@@ -56,6 +56,7 @@ object cell_get(object cell);
 /* Prototypes for Lisp built-in functions. */
 
 extern object Cyc_global_variables;
+extern object Cyc_command_line_arguments;
 object Cyc_get_global_variables();
 object Cyc_get_cvar(object var);
 object Cyc_set_cvar(object var, object value);