cmake: CheckTypeSize does not work correctly for types > 255?

[Viatorus]

The custom shipped CheckTypeSize module does not handle types greater than 255 bytes correctly.

Version of emscripten/emsdk:
3.1.23

Testing source

cmake_minimum_required(VERSION 3.10)

project(sizeof-test)

include(CheckTypeSize)

check_type_size("char[15]" size1)
check_type_size("char[2048]" size2)
check_type_size("char[2049]" size3)
check_type_size("char[2047]" size4)

message(WARNING "${size1} ${size2} ${size3} ${size4}") # 15 0 1 255

-- Check size of char[15]
-- Check size of char[15] - done
-- Check size of char[2048]
-- Check size of char[2048] - done
-- Check size of char[2049]
-- Check size of char[2049] - done
-- Check size of char[2047]
-- Check size of char[2047] - done
CMake Warning at CMakeLists.txt:63 (message):
  15 0 1 255

[sbc100]

The problem seems to date back to b206b9e. We apparently override CheckTypeSize but we use the return value of the executable, which is only allowed to be in the range 0-255.