Index: cmake/FindBISON.cmake
--- cmake/FindBISON.cmake.orig
+++ cmake/FindBISON.cmake
@@ -315,7 +315,8 @@ if(BISON_EXECUTABLE)
       unset(_BISON_CMP0088)
 
       add_custom_command(OUTPUT ${BISON_TARGET_outputs}
-        COMMAND ${CMAKE_COMMAND} -E env "M4=${BISON_M4_EXECUTABLE}"
+#        COMMAND ${CMAKE_COMMAND} -E env "M4=${BISON_M4_EXECUTABLE}"
+        COMMAND ${CMAKE_COMMAND} -E env "HOTFIXM4=${BISON_M4_EXECUTABLE}"
           ${BISON_EXECUTABLE} ${BISON_TARGET_cmdopt} -o ${BisonOutput} ${_BisonInput}
         VERBATIM
         DEPENDS ${_BisonInput}
