diff --git a/CMakeLists.txt b/CMakeLists.txt
index b70bb7c4..d9c18554 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,5 +1,5 @@
 cmake_minimum_required(VERSION 3.5)
-project(nextpnr CXX)
+project(nextpnr CXX C)
 
 option(BUILD_GUI "Build GUI" ON)
 option(BUILD_PYTHON "Build Python Integration" ON)