[LyX/master] Allow to provide xunicode.

[Juergen Spitzmueller]

commit 9302b1ae6324495c37c1b6ccf0870abb843779a9
Author: Juergen Spitzmueller <sp...@lyx.org>
Date:   Fri Sep 15 09:36:16 2017 +0200

    Allow to provide xunicode.
---
 src/BufferParams.cpp |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/src/BufferParams.cpp b/src/BufferParams.cpp
index 060d9e4..2f7058a 100644
--- a/src/BufferParams.cpp
+++ b/src/BufferParams.cpp
@@ -2286,7 +2286,8 @@ bool BufferParams::writeLaTeX(otexstream & os, 
LaTeXFeatures & features,
        // (the rest is obsoleted by the new TU encoding).
        // It needs to be loaded at least after amsmath, amssymb,
        // esint and the other packages that provide special glyphs
-       if (features.mustProvide("tipa") && useNonTeXFonts) {
+       if (features.mustProvide("tipa") && useNonTeXFonts
+           && !features.isProvided("xunicode")) {
                // The package officially only supports XeTeX, but also works
                // with LuaTeX. Thus we work around its XeTeX test.
                if (features.runparams().flavor != OutputParams::XETEX) {