diff --git a/CMakeLists.txt b/CMakeLists.txt
index 964a805..75acbb2 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 2.8)
+cmake_minimum_required(VERSION 3.4)
 
 project(wds CXX)
 
diff --git a/libwds/rtsp/CMakeLists.txt b/libwds/rtsp/CMakeLists.txt
index 6b4c37b..3f992e3 100644
--- a/libwds/rtsp/CMakeLists.txt
+++ b/libwds/rtsp/CMakeLists.txt
@@ -14,7 +14,7 @@ if (CMAKE_BUILD_TYPE STREQUAL "Debug")
 endif (CMAKE_BUILD_TYPE STREQUAL "Debug")
 
 find_package(BISON REQUIRED)
-BISON_TARGET(Parser parser.ypp ${PARSER_GEN_DIR}/parser.cpp COMPILE_FLAGS "-l -p wds_ ${PARSER_DEBUG_OPTIONS}")
+BISON_TARGET(Parser parser.ypp ${PARSER_GEN_DIR}/parser.cpp COMPILE_FLAGS "-l -p wds_ ${PARSER_DEBUG_OPTIONS}" DEFINES_FILE ${PARSER_GEN_DIR}/parser.h)
 
 find_package(FLEX REQUIRED)
 FLEX_TARGET(MessageLexer messagelexer.l ${PARSER_GEN_DIR}/messagescanner.cpp COMPILE_FLAGS "-L -P message_ ${PARSER_DEBUG_OPTIONS}")