Add support for modular build structure. (#29)

This is part of the effort to make the Boost libraries "modular" for build and consumption. See https://lists.boost.org/Archives/boost/2024/01/255704.php and https://github.com/grafikrobot/boost-b2-modular/blob/b2-modular/README.adoc for more information.

This PR depends on the following other PRs being merged to both develop and master branches of the respective repos:

- https://github.com/boostorg/boost/pull/854

This PR will be changed to ready for review, i.e. not draft, when the above are merged. Do not merge this one until that time.

build.jam

@@ -0,0 +1,26 @@
+# Copyright René Ferdinand Rivera Morell 2023-2024
+# Distributed under the Boost Software License, Version 1.0.
+# (See accompanying file LICENSE_1_0.txt or copy at
+# http://www.boost.org/LICENSE_1_0.txt)
+
+require-b2 5.2 ;
+
+constant boost_dependencies :
+    /boost/assert//boost_assert
+    /boost/config//boost_config
+    /boost/smart_ptr//boost_smart_ptr
+    /boost/throw_exception//boost_throw_exception ;
+
+project /boost/conversion
+    : common-requirements
+        <include>include
+    ;
+
+explicit
+    [ alias boost_conversion : : : : <library>$(boost_dependencies) ]
+    [ alias all : boost_conversion test ]
+    ;
+
+call-if : boost-library conversion
+    ;
+

doc/conversion.qbk

@@ -1,6 +1,6 @@
 [/
     Copyright 2016 Mikhail Maximov.
-    Copyright Antony Polukhin, 2020-2023.
+    Copyright Antony Polukhin, 2020-2024.
 
     Distributed under the Boost Software License, Version 1.0. (See accompanying
     file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt">http://www.boost.org/LICENSE_1_0.txt</a>)
@@ -12,7 +12,7 @@
     [id conversion]
     [version 1.7]
     [authors [Stroustrup, Bjarne], [Abrahams, Dave], [Rasin, Boris], [Polukhin, Antony]]
-    [copyright 2001 Beman Dawes, 2014-2023 Antony Polukhin]
+    [copyright 2001 Beman Dawes, 2014-2024 Antony Polukhin]
     [license
         Distributed under the Boost Software License, Version 1.0.
         (See accompanying file LICENSE_1_0.txt or copy at
@@ -30,8 +30,7 @@ The Conversion Library improves program safety and clarity by performing
 otherwise messy conversions. It includes cast-style function templates designed 
 to complement the C++ Standard's built-in casts.
 
-To reduce coupling, particularly to standard library IOStreams, 
-the Boost Conversion Library is supplied by several headers:
+To reduce coupling, the Boost Conversion Library is supplied by several headers:
 
 # The [@boost:boost/polymorphic_cast.hpp boost/polymorphic_cast.hpp] header
   provides [link polymorphic_cast `polymorphic_cast<>`] and
@@ -42,8 +41,6 @@ the Boost Conversion Library is supplied by several headers:
   [link polymorphic_pointer_cast `polymorphic_pointer_downcast<>`]
 # The [@boost:boost/implicit_cast.hpp boost/implicit_cast.hpp] header provides `implicit_cast<>` 
   to perform implicit casts only (no down-cast, no void*->T*, no U->T if T has only explicit constructors for U).
-# The [@boost:boost/lexical_cast.hpp boost/lexical_cast.hpp] header 
-  provides [@boost:doc/libs/release/libs/lexical_cast/ `lexical_cast<>`] general literal text conversions, such as an `int` represented as a `string`, or vice-versa. 
 
 [endsect]
 

include/boost/polymorphic_pointer_cast.hpp

@@ -1,6 +1,6 @@
 //  boost polymorphic_pointer_cast.hpp header file  ----------------------------------------------//
 //  (C) Copyright Boris Rasin, 2014-2021.
-//  (C) Copyright Antony Polukhin, 2014-2023.
+//  (C) Copyright Antony Polukhin, 2014-2024.
 //  Distributed under the Boost
 //  Software License, Version 1.0. (See accompanying file
 //  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)

index.html

@@ -3,7 +3,7 @@
  Copyright (c) 2016 Mikhail Maximov
  vigorous.activity at gmail dot com
 
- Copyright (c) Antony Polukhin, 2021-2023
+ Copyright (c) Antony Polukhin, 2021-2024
 
  Distributed under the Boost Software License,
  Version 1.0. (See accompanying file LICENSE_1_0.txt
@@ -33,7 +33,7 @@ boost-no-inspect
     <a href="../../doc/html/conversion.html">../../doc/html/conversion.html</a>
   </p>
   <p>
-    &copy; Antony Polukhin, 2014-2023
+    &copy; Antony Polukhin, 2014-2024
   </p>
 </body>
 </html>

test/Jamfile.v2

@@ -1,18 +1,20 @@
 # Copyright (C) 2001-2003 Douglas Gregor
-# Copyright (C) Antony Polukhin, 2011-2023
+# Copyright (C) Antony Polukhin, 2011-2024
 #
 # Distributed under the Boost Software License, Version 1.0. (See accompanying
 # file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
 #
 
+require-b2 5.0.1 ;
+import-search /boost/config/checks ;
+import config : requires ;
 import testing ;
 import feature ;
 
-import ../../config/checks/config : requires ;
-
 project
     : requirements
-        [ requires cxx11_rvalue_references ]
+        <library>/boost/conversion//boost_conversion
+        [ requires cxx11_decltype ]
         # default to all warnings on:
         <warnings>all
         # set warnings as errors for those compilers we know we get warning free:

test/appveyor.yml

@@ -2,7 +2,7 @@
 # subject to the Boost Software License, Version 1.0. (See accompanying
 # file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
 #
-# Copyright Antony Polukhin, 2016-2023.
+# Copyright Antony Polukhin, 2016-2024.
 
 #
 # See https://svn.boost.org/trac/boost/wiki/TravisCoverals for description of this file