Support building under CYGWIN

- Parse CHANGES file with Universal Python line endings in case
  the source tree was checked out with Windows line endings.
- Use our own clone of strnlen_s which might not be available
  everywhere.

Fixes https://github.com/KhronosGroup/SPIRV-Tools/issues/508
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 891828b..6017793 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -71,6 +71,7 @@
   binary_endianness_test.cpp
   binary_header_get_test.cpp
   binary_parse_test.cpp
+  binary_strnlen_s_test.cpp
   binary_to_text_test.cpp
   binary_to_text.literal_test.cpp
   capability_set_test.cpp