diff --git a/source/CMakeLists.txt b/source/CMakeLists.txt
index 8a1304c..a6b7372 100644
--- a/source/CMakeLists.txt
+++ b/source/CMakeLists.txt
@@ -43,3 +43,13 @@ else()
         # GCC specific flags here
     endif()
 endif()
+
+option(BUILD_WASI_SUPPORT "Build with WASI support" OFF)
+
+if (BUILD_WASI_SUPPORT)
+    if (WASIENV)
+        target_compile_definitions(m3 PUBLIC d_m3HasMetaWASI)
+    elseif (NOT EMSCRIPTEN)
+        target_compile_definitions(m3 PUBLIC d_m3HasWASI)
+    endif()
+endif()