[LyX/master] Limit RTL hack to classic engines (#12919)

[Juergen Spitzmueller]

commit 04bfbc0f7a1964790256117f146ba040054b34b2
Author: Juergen Spitzmueller <spitz at lyx.org>
Date:   Sat Sep 30 16:59:37 2023 +0200

    Limit RTL hack to classic engines (#12919)
    
    It breaks with LuaTeX, is definitely not needed with XeTeX, and it is
    doubted whether it is needed at all (but this needs further testing).
---
 src/BufferParams.cpp |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/src/BufferParams.cpp b/src/BufferParams.cpp
index 8a8422a..36ebb21 100644
--- a/src/BufferParams.cpp
+++ b/src/BufferParams.cpp
@@ -1593,7 +1593,8 @@ void BufferParams::validate(LaTeXFeatures & features) const
 {
 	features.require(documentClass().required());
 
-	if (columns > 1 && language->rightToLeft())
+	if (columns > 1 && language->rightToLeft()
+	    && !features.runparams().isFullUnicode())
 		features.require("rtloutputdblcol");
 
 	if (output_changes) {