Add configuration for no_unique_address attribute

Author: patrickroberts

CMakeLists.txt

@@ -23,6 +23,27 @@ option(
     ${PROJECT_IS_TOP_LEVEL}
 )
 
+# [CPP.NO_FLAG_FORKING]
+if(CMAKE_CXX_COMPILER_ID STREQUAL "MSVC")
+    set(BEMAN_ANY_VIEW_NO_UNIQUE_ADDRESS
+        "[[msvc::no_unique_address]]"
+        CACHE STRING
+        "Name of C++ attribute for empty base optimization of data members"
+    )
+else()
+    set(BEMAN_ANY_VIEW_NO_UNIQUE_ADDRESS
+        "[[no_unique_address]]"
+        CACHE STRING
+        "Name of C++ attribute for empty base optimization of data members"
+    )
+endif()
+
+configure_file(
+    include/beman/any_view/config.hpp.in
+    include/beman/any_view/config.hpp
+    @ONLY
+)
+
 set(CMAKE_CXX_EXTENSIONS OFF)
 
 include(FetchContent)
@@ -36,6 +57,7 @@ target_include_directories(
     beman.any_view
     INTERFACE
         $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>
+        $<BUILD_INTERFACE:${PROJECT_BINARY_DIR}/include>
         $<INSTALL_INTERFACE:include>
 )
 
@@ -51,6 +73,7 @@ install(
     DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/${CMAKE_PROJECT_NAME}
     FILES_MATCHING
     PATTERN "${CMAKE_CURRENT_SOURCE_DIR}/include/beman/any_view/*.hpp"
+    PATTERN "${CMAKE_CURRENT_BINARY_DIR}/include/beman/any_view/*.hpp"
 )
 
 macro(beman_add_executable)

include/beman/any_view/config.hpp.in

@@ -0,0 +1,8 @@
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+#ifndef BEMAN_ANY_VIEW_CONFIG_HPP
+#define BEMAN_ANY_VIEW_CONFIG_HPP
+
+#cmakedefine BEMAN_ANY_VIEW_NO_UNIQUE_ADDRESS() @BEMAN_ANY_VIEW_NO_UNIQUE_ADDRESS@
+
+#endif // BEMAN_ANY_VIEW_CONFIG_HPP

include/beman/any_view/detail/iterator_adaptor.hpp

@@ -19,8 +19,8 @@ template <class ElementT,
           std::input_or_output_iterator IteratorT,
           std::sentinel_for<IteratorT>  SentinelT>
 class iterator_adaptor final : public iterator_interface<ElementT, RefT, RValueRefT, DiffT> {
-    [[no_unique_address]] IteratorT iterator;
-    [[no_unique_address]] SentinelT sentinel;
+    BEMAN_ANY_VIEW_NO_UNIQUE_ADDRESS() IteratorT iterator;
+    BEMAN_ANY_VIEW_NO_UNIQUE_ADDRESS() SentinelT sentinel;
 
     using iterator_interface = detail::iterator_interface<ElementT, RefT, RValueRefT, DiffT>;
     using pointer            = std::add_pointer_t<RefT>;

include/beman/any_view/detail/view_adaptor.hpp

@@ -12,7 +12,7 @@ class view_adaptor final : public view_interface<IterConceptT, ElementT, RefT, R
     using iterator  = detail::any_iterator<IterConceptT, ElementT, RefT, RValueRefT, DiffT>;
     using size_type = std::make_unsigned_t<DiffT>;
 
-    [[no_unique_address]] ViewT view;
+    BEMAN_ANY_VIEW_NO_UNIQUE_ADDRESS() ViewT view;
 
     static constexpr auto get_noexcept() { return std::is_nothrow_move_constructible_v<ViewT>; }