Add support for modular build structure. (#21)

* Make the library modular usable.

* Switch to library requirements instead of source. As source puts extra source in install targets.

* Add missing import-search for cconfig/predef checks.

* Add requires-b2 check to top-level build file.

* Update dependencies.

* Bump B2 require to 5.2

* Remove repeated import-search.

* Move inter-lib dependencies to a project variable and into the build targets.

* Adjust doc build to avoid boost-root references.

* Update build deps.

build.jam

@@ -0,0 +1,26 @@
+# Copyright René Ferdinand Rivera Morell 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/core//boost_core
+    /boost/type_traits//boost_type_traits ;
+
+project /boost/scope
+    : common-requirements
+        <include>include
+    ;
+
+explicit
+    [ alias boost_scope : : : : <library>$(boost_dependencies) ]
+    [ alias all : boost_scope test ]
+    ;
+
+call-if : boost-library scope
+    ;
+

doc/Jamfile

@@ -56,7 +56,7 @@ local doxygen_params =
 
 local top_level_includes =
     [ glob
-        ../../../boost/scope/*.hpp
+        ../include/boost/scope/*.hpp
     ] ;
 
 

test/Jamfile

@@ -4,14 +4,18 @@
 # (See accompanying file LICENSE_1_0.txt or copy at
 # https://www.boost.org/LICENSE_1_0.txt)
 
+require-b2 5.0.1 ;
+
 import testing ;
 import path ;
 import regex ;
 import os ;
-import ../../config/checks/config : requires ;
+import-search /boost/config/checks ;
+import config : requires ;
 
 project
     : requirements
+        <library>/boost/scope//boost_scope
         <include>common
 
         <c++-template-depth>1024
@@ -43,6 +47,8 @@ project
         <target-os>windows:<define>_CRT_SECURE_NO_DEPRECATE
     ;
 
+path-constant SCOPE_INCLUDE_DIR : ../include ;
+
 # this rule enumerates through all the sources and invokes
 # the run rule for each source, the result is a list of all
 # the run rules, which we can pass on to the test_suite rule:
@@ -53,7 +59,7 @@ rule test_all
 
     if ! [ os.environ BOOST_SCOPE_TEST_WITHOUT_SELF_CONTAINED_HEADER_TESTS ]
     {
-        local headers_path = [ path.make $(BOOST_ROOT)/libs/scope/include/boost/scope ] ;
+        local headers_path = [ path.make $(SCOPE_INCLUDE_DIR)/boost/scope ] ;
         for file in [ path.glob-tree $(headers_path) : *.hpp : detail ]
         {
             local rel_file = [ path.relative-to $(headers_path) $(file) ] ;