[LyX/master] Fix compilation on cygwin

[Enrico Forestieri]

commit 0d204c4e87d684fd45e6b4aaabef74889b3471a8
Author: Enrico Forestieri <forenr at lyx.org>
Date:   Mon Nov 30 11:32:35 2020 +0100

    Fix compilation on cygwin
---
 src/LaTeXFeatures.h |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/src/LaTeXFeatures.h b/src/LaTeXFeatures.h
index 4590bce..91d27e8 100644
--- a/src/LaTeXFeatures.h
+++ b/src/LaTeXFeatures.h
@@ -13,7 +13,7 @@
 #ifndef LATEXFEATURES_H
 #define LATEXFEATURES_H
 
-#include "support/strfwd.h"
+#include "support/docstring.h"
 
 #include <set>
 #include <list>