fix: a bug (--2c) reported by Rui Chen w.r.t. nodes with no input

Nodes with no input would produced C code that can not compile

The bug was introduced in sha:bec478ee

.gitlab-ci.yml

@@ -14,11 +14,11 @@ lv6-man:
   allow_failure: true
   script:
     - cd lv6-ref-man
-    - make 
+    - make
   artifacts:
     paths:
       - doc
-  
+
 build:
   stage: build
   script:
@@ -45,7 +45,7 @@ test_opam_test:
 # can only be updated if the whole pipeline succeeds (to be able te get
 # the release number). The idea is to rerun this job manually  when it
 # is the case.
-  
+
 .test_opam_on_mac:
   stage: test
   tags:
@@ -60,7 +60,7 @@ test_opam_test:
 
 # automating version numbering
 release:
-  image: node:14-buster-slim
+  image: node:19-buster-slim
   stage: release
   before_script:
     - apt-get update && apt-get install -y --no-install-recommends git-core ca-certificates