diff --git a/CMakeLists.txt b/CMakeLists.txt
index 9cb580c13f..23360c1e28 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -35,10 +35,13 @@ add_subdirectory(evmc)
 
 cable_configure_compiler(NO_PEDANTIC NO_CONVERSION_WARNINGS)
 if(CABLE_COMPILER_GNULIKE)
+    add_compile_options(-Wno-attributes)  # Allow using unknown attributes.
+
     # Prepend to CXX flags to allow overriding.
     set(CMAKE_CXX_FLAGS "-fvisibility=hidden ${CMAKE_CXX_FLAGS}")
 elseif(MSVC)
     add_compile_options(/wd4324)  # Disabled warning about alignment casued by alignas.
+    add_compile_options(/wd5030)  # Allow using unknown attributes.
 endif()
 
 set(include_dir ${CMAKE_CURRENT_SOURCE_DIR}/include)