Cleanup shellcheck warnings in autogen.sh

autogen.sh

 #!/bin/sh
 
-if [ -x "`which autoreconf 2>/dev/null`" ] ; then
+if command -v autoreconf; then
   opt="-i -f -W all,error"
 
-  for i in $@; do
+  for i in "$@"; do
     case "$i" in
       -v)
         opt="${opt} -v"
@@ -11,6 +11,7 @@ if [ -x "`which autoreconf 2>/dev/null`" ] ; then
     esac
   done
 
+  # shellcheck disable=SC2086
   exec autoreconf $opt
 fi
 

changes/ticket26069

+  o Code simplification and refactoring (shell scripts):
+    - Cleanup autogen.sh to silence shellcheck warnings. Closes ticket 26069.