Remove USE_VENDORED_TL_EXPECTED option

Author: otamachan

tl_expected/CMakeLists.txt

@@ -7,13 +7,7 @@ project(tl_expected
 
 find_package(ament_cmake REQUIRED)
 
-option(USE_VENDORED_TL_EXPECTED "Use vendored tl_expected instead of system libexpected-dev" OFF)
-
 add_library(tl_expected INTERFACE)
-
-if(USE_VENDORED_TL_EXPECTED)
-  target_compile_definitions(tl_expected INTERFACE USE_VENDORED_TL_EXPECTED)
-endif()
 target_include_directories(tl_expected INTERFACE
   $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
   $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>)

tl_expected/include/tl_expected/expected.hpp

@@ -13,12 +13,12 @@
 // <http://creativecommons.org/publicdomain/zero/1.0/>.
 ///
 
-// If the system header is available and vendored version is not explicitly
-// requested, redirect to the system header with a deprecation warning.
-#if !defined(USE_VENDORED_TL_EXPECTED) && __has_include(<tl/expected.hpp>)
-#warning "tl_expected/expected.hpp is deprecated. Use <tl/expected.hpp> from libexpected-dev, or <rcpputils/tl_expected/expected.hpp> if the system header is not available."
+// If the system header is available, redirect to it.
+// Otherwise, fall back to the vendored version with a deprecation warning.
+#if __has_include(<tl/expected.hpp>)
 #include <tl/expected.hpp>
 #else
+#warning "tl_expected/expected.hpp is deprecated. Please install libexpected-dev and use <tl/expected.hpp> instead."
 
 #ifndef TL_EXPECTED_HPP
 #define TL_EXPECTED_HPP