--- a/src/cmake/flexbison.cmake
+++ b/src/cmake/flexbison.cmake
@@ -49,6 +49,8 @@
         set ( flexoutputcxx "${CMAKE_CURRENT_BINARY_DIR}/${flexsrc_we}.cpp" )
         set ( ${srclist} ${${srclist}} ${bisonoutputcxx} ${flexoutputcxx} )
 
+        # Do not do this as it adds C:/msys64/include to the search path
+        # for all compilation.
         # Be really sure that we prefer the FlexLexer.h that comes with
         # the flex binary we're using, not some other one in the system.
         get_filename_component ( FLEX_UP ${FLEX_EXECUTABLE} PATH )
@@ -57,7 +59,10 @@
         if (VERBOSE)
             message (STATUS "Flex include dir = ${FLEX_INCLUDE_DIR}")
         endif ()
-        include_directories ( ${FLEX_INCLUDE_DIR} )
+        # include_directories ( ${FLEX_INCLUDE_DIR} )
+        # Instead try ..
+        MESSAGE (STATUS "  FLEX_INCLUDE_DIR ${FLEX_INCLUDE_DIR}")
+        file(COPY ${FLEX_INCLUDE_DIR}/FlexLexer.h DESTINATION ${CMAKE_CURRENT_BINARY_DIR}/)
 
         # include_directories ( ${CMAKE_CURRENT_BINARY_DIR} )
         include_directories ( ${CMAKE_CURRENT_SOURCE_DIR} )