diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 8bf896bb1..d61757cc1 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -1,8 +1,19 @@
 project(minetest)
 
+INCLUDE(CheckTypeSize)
 INCLUDE(CheckIncludeFiles)
 INCLUDE(CheckLibraryExists)
 
+check_type_size(int SIZEOF_INT BUILTIN_TYPES_ONLY LANGUAGE CXX)
+if(SIZEOF_INT LESS 4)
+	message(FATAL_ERROR "Minetest will not work with int less than 32 bits wide.")
+endif()
+
+check_type_size(size_t SIZEOF_SIZE_T LANGUAGE CXX)
+if(SIZEOF_SIZE_T LESS 4)
+	message(FATAL_ERROR "Minetest will not work with size_t less than 32 bits wide.")
+endif()
+
 # Add custom SemiDebug build mode
 set(CMAKE_CXX_FLAGS_SEMIDEBUG "-O1 -g -Wall" CACHE STRING
 	"Flags used by the C++ compiler during semidebug builds."