diff --git a/encode/CMakeLists.txt b/encode/CMakeLists.txt
index 9a25c3b3f5977b4e215e9595d0a2fcd12e1d5809..b7c7dd78968466364d580e02403c6a1c1a8ec3a7 100644
--- a/encode/CMakeLists.txt
+++ b/encode/CMakeLists.txt
@@ -22,6 +22,7 @@ set(HEADER
 )
 
 add_library(encode OBJECT ${SOURCE})
+target_compile_features(encode PUBLIC c_std_99)
 target_include_directories(encode PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
 target_link_libraries(encode xpdev)
 install(