diff --git a/CMakeLists.txt b/CMakeLists.txt
index ec42bc99..d80eb48b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -24,7 +24,7 @@ endif()
 #string(TOLOWER ${OPENJPEG_NAMESPACE} OPENJPEG_LIBRARY_NAME)
 set(OPENJPEG_LIBRARY_NAME openjp2)
 
-project(${OPENJPEG_NAMESPACE})
+project(${OPENJPEG_NAMESPACE} C)
 
 # Do full dependency headers.
 include_regular_expression("^.*$")