[libxml2] Set project language to C

[Nick Wellnhofer <nwellnhof src gnome org>]

commit d514e2bd40b875e91945ecb27f25aeb0e63ea17d
Author: Markus Rickert <rickert fortiss org>
Date:   Sun Jul 12 18:42:49 2020 +0200

    Set project language to C

 CMakeLists.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/CMakeLists.txt b/CMakeLists.txt
index fc163f02..c918125a 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,6 +1,6 @@
 cmake_minimum_required(VERSION 3.14)
 
-project(libxml2)
+project(libxml2 C)
 
 include(CheckCSourceCompiles)
 include(CheckFunctionExists)