Fix build on Alpine

CMakeLists.txt

@@ -52,15 +52,6 @@ if (WITH_LUA)
 	list (APPEND project_libraries ${lua_LIBRARIES})
 	include_directories (${lua_INCLUDE_DIRS})
 	link_directories (${lua_LIBRARY_DIRS})
-
-	include (CheckTypeSize)
-	set (CMAKE_REQUIRED_LIBRARIES ${lua_LIBRARIES})
-	set (CMAKE_REQUIRED_INCLUDES ${lua_INCLUDE_DIRS})
-	set (CMAKE_EXTRA_INCLUDE_FILES "lua.h")
-	CHECK_TYPE_SIZE (lua_Integer LUA_INTEGER)
-	if (NOT HAVE_LUA_INTEGER OR LUA_INTEGER LESS 8)
-		message (FATAL_ERROR "Lua must have at least 64-bit integers")
-	endif ()
 endif ()
 
 pkg_check_modules (x11 x11 xrender xft fontconfig libpng)

hex.c

@@ -71,6 +71,12 @@ enum
 #include <lua.h>
 #include <lualib.h>
 #include <lauxlib.h>
+
+// This test is too annoying to do in CMake due to CheckTypeSize() being unable
+// to take link_directories(), and the Lua constant is documented.
+#if LUA_MAXINTEGER < INT64_MAX
+#error Lua must have at least 64-bit integers
+#endif
 #endif // WITH_LUA
 
 #define APP_TITLE  PROGRAM_NAME         ///< Left top corner