>>>>> On Wed, 15 Jun 2022 08:59:20 +0800, Po Lu <luangruo@yahoo.com> said:

    Po> Eli Zaretskii <eliz@gnu.org> writes:
    >> Thanks for testing, I will let it to Po Lu to decide whether that's
    >> the proper fix in this case.

    Po> Non-toolkit scroll bars use different kinds of events compared to
    Po> toolkit scroll bars.  PGTK only implements the latter kind, so turning
    Po> toolkit scroll bars off should trigger this piece of configure.ac:

    Po>   elif test "${window_system}" != "x11" && "${window_system}" != "none"; then
    Po>     AC_MSG_ERROR(Non-toolkit scroll bars are not implemented for your system)
    Po>   fi

    Po> Perhaps Sameer's configure script is out of date and needs to be
    Po> regenerated.

configure is written in sh, not in C, so you need

diff --git a/configure.ac b/configure.ac
index 5b86e90925..c91b7de322 100644
--- a/configure.ac
+++ b/configure.ac
@@ -3436,7 +3436,7 @@ AC_DEFUN
     AC_DEFINE(USE_TOOLKIT_SCROLL_BARS)
     USE_TOOLKIT_SCROLL_BARS=yes
   fi
-elif test "${window_system}" != "x11" && "${window_system}" != "none"; then
+elif test "${window_system}" != "x11" && test "${window_system}" != "none"; then
   AC_MSG_ERROR(Non-toolkit scroll bars are not implemented for your system)
 fi


(or use -a to avoid repeating the 'test')

Robert
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