Check that 'configure' is generated by GNU Autoconf 2.69 (GH-28152)

.github/workflows/build.yml

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 05bdf24..27e07a5 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -84,6 +84,8 @@
         run: make smelly
       - name: Check limited ABI symbols
         run: make check-limited-abi
+      - name: Check Autoconf version 2.69
+        run: grep "Generated by GNU Autoconf 2.69" configure
 
   build_win32:
     name: 'Windows (x86)'