diff --git a/.github/workflows/docsygen.yml b/.github/workflows/docsygen.yml
index af53a40f..dd68a27f 100644
--- a/.github/workflows/docsygen.yml
+++ b/.github/workflows/docsygen.yml
@@ -1,7 +1,11 @@
+---
 name: Docs
-on: [push]
+on:
+  push:
+    branches:
+      - 'main'
 jobs:
-  build-and-deploy:
+  build-and-docs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
@@ -25,7 +29,7 @@ jobs:
           spellers: false
           fst: hfst
 
-# Mermaid processing starts here:
+      # Mermaid processing starts here:
       - name: get list of files
         id: getfile
         run: |
@@ -35,7 +39,7 @@ jobs:
         run: |
           echo ${{ steps.getfile.outputs.files }}
 
-# The actual Mermaid compilation
+      # The actual Mermaid compilation
       - name: compile mermaid
         uses: divvun/compile-mermaid-markdown-action@main
         with:
@@ -43,14 +47,14 @@ jobs:
           output: 'lang/docs/mermaid-svgs'
         env:
           HIDE_CODEBLOCKS: 1
-# The next one must be declared, with an empty value, for paths to work for us:
+          # The next one must be declared, with an empty value, for paths to work for us:
           ABSOLUTE_IMAGE_LINKS:
           OUTPUT_FILE_TYPE: "svg"
 
       - name: list generated svg fils
         run: |
           cd lang && ls -l docs/mermaid-svgs
-# Mermaid processing ends here
+      # Mermaid processing ends here
 
       - name: deploy gh pages
         uses: peaceiris/actions-gh-pages@v3
diff --git a/m4/ax_compare_version.m4 b/m4/ax_compare_version.m4
index 74dc0fdd..ffb4997e 100644
--- a/m4/ax_compare_version.m4
+++ b/m4/ax_compare_version.m4
@@ -1,5 +1,5 @@
 # ===========================================================================
-#    http://www.gnu.org/software/autoconf-archive/ax_compare_version.html
+#    https://www.gnu.org/software/autoconf-archive/ax_compare_version.html
 # ===========================================================================
 #
 # SYNOPSIS
@@ -79,7 +79,7 @@
 #   and this notice are preserved. This file is offered as-is, without any
 #   warranty.
 
-#serial 11
+#serial 13
 
 dnl #########################################################################
 AC_DEFUN([AX_COMPARE_VERSION], [
@@ -146,7 +146,7 @@ x$B" | sed 's/^ *//' | sort -r | sed "s/x${A}/true/;s/x${B}/false/;1q"`
     ],
     [.+],[
       AC_WARNING(
-        [illegal OP numeric parameter: $2])
+        [invalid OP numeric parameter: $2])
     ],[])
 
     # Pad zeros at end of numbers to make same length.
@@ -162,7 +162,7 @@ x$B" | sed 's/^ *//' | sort -r | sed "s/x${A}/true/;s/x${B}/false/;1q"`
     [ne],[
       test "x$A" != "x$B" && ax_compare_version=true
     ],[
-      AC_WARNING([illegal OP parameter: $2])
+      AC_WARNING([invalid OP parameter: $2])
     ])
   ])
 
diff --git a/m4/giella-macros.m4 b/m4/giella-macros.m4
index a439cec9..708aa8ba 100644
--- a/m4/giella-macros.m4
+++ b/m4/giella-macros.m4
@@ -667,13 +667,13 @@ AC_PATH_PROG([GTGRAMTOOL], [gtgramtool], [false])
 AS_IF([test "x$enable_grammarchecker" != "xno"],
     AX_PYTHON_MODULE(pip)
     AC_MSG_CHECKING([whether we have gtgramtool])
-    AS_IF([test x$GTGRAMTOOL = xfalse], 
+    AS_IF([test x$GTGRAMTOOL = xfalse],
     [AC_MSG_ERROR([gtgramtool is needed for --enable grammarchecker.
         on debian/ubuntu: sudo apt update; sudo apt install pipx; pipx ensurepath
         on macbrew: brew install pipx; pipx ensurepath
         then: pipx install git+https://github.com/divvun/giellaltgramtools
       ])]),
-    AC_MSG_RESULT(yes))
+    AC_MSG_RESULT([yes]))
 _gtgramtool_min_version=0.7.0
 gtgramtool_too_old_message="gtgramtool needs to be updated.
     If you installed it with pipx, run:
@@ -683,12 +683,12 @@ AS_IF([test "x${GTGRAMTOOL}" != xno],
         [_gtgramtool_version=$( "${GTGRAMTOOL}" --version | sed -e 's/^.*version //')],
         [_gtgramtool_version=0])
 AC_MSG_RESULT([$_gtgramtool_version])
+AC_MSG_CHECKING([whether the gtgramtool version is at least $_gtgramtool_min_version])
+AX_COMPARE_VERSION([$_gtgramtool_version], [ge], [$_gtgramtool_min_version],
+                   [gtgramtool_version_ok=yes], [gtgramtool_version_ok=no])
+AC_MSG_RESULT([$gtgramtool_version_ok])
 AS_IF([test "x$enable_grammarchecker" != "xno"], 
-      AC_MSG_CHECKING([whether the gtgramtool version is at least $_gtgramtool_min_version])
-      AX_COMPARE_VERSION([$_gtgramtool_version], [ge], [$_gtgramtool_min_version],
-                         [gtgramtool_version_ok=yes], [gtgramtool_version_ok=no])
-    AS_IF([test "x${gtgramtool_version_ok}" != xno],
-          [AC_MSG_RESULT([$gtgramtool_version_ok])],
+    AS_IF([test "x${gtgramtool_version_ok}" != xno],,
           [AC_MSG_ERROR([$gtgramtool_too_old_message])]))