diff --git a/development/cmake/src/tex2lyx/CMakeLists.txt b/development/cmake/src/tex2lyx/CMakeLists.txt
index 5fd3df8078..455b93e7d0 100644
--- a/development/cmake/src/tex2lyx/CMakeLists.txt
+++ b/development/cmake/src/tex2lyx/CMakeLists.txt
@@ -18,7 +18,7 @@ set(LINKED_FILES
 )
 
 set(tex2lyx_sources
-	${TOP_SRC_DIR}/src/tex2lyx/boost.cpp
+	${TOP_SRC_DIR}/src/tex2lyx/boost.C
 	${TOP_SRC_DIR}/src/tex2lyx/context.C
 	${TOP_SRC_DIR}/src/tex2lyx/gettext.C
 	${TOP_SRC_DIR}/src/tex2lyx/lengthcommon.C