Add support for modular build structure. (#752)

* Make the library modular usable.

* Add missing modular build.jam. And fix gitignore that caused it to be originally deleted!

* 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.

* Bump B2 require to 5.2

* Update copyright dates.

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

* Update build deps.

.gitignore

@@ -41,3 +41,5 @@ graph_info.json
 # clangd
 compile_commands.json
 .clangd/
+
+!build.jam

build.jam

@@ -0,0 +1,34 @@
+# 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/concept_check//boost_concept_check
+    /boost/config//boost_config
+    /boost/container_hash//boost_container_hash
+    /boost/core//boost_core
+    /boost/filesystem//boost_filesystem
+    /boost/integer//boost_integer
+    /boost/iterator//boost_iterator
+    /boost/mp11//boost_mp11
+    /boost/preprocessor//boost_preprocessor
+    /boost/type_traits//boost_type_traits
+    /boost/variant2//boost_variant2 ;
+
+project /boost/gil
+    : common-requirements
+        <include>include
+    ;
+
+explicit
+    [ alias boost_gil : : : : <library>$(boost_dependencies) ]
+    [ alias all : boost_gil example test ]
+    ;
+
+call-if : boost-library gil
+    ;
+

example/Jamfile

@@ -6,7 +6,8 @@
 # Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
 # http://www.boost.org/LICENSE_1_0.txt)
 
-import ../../config/checks/config : requires ;
+import-search /boost/config/checks ;
+import config : requires ;
 import regex ;
 
 using libjpeg : : : : true ; # work around bug on master
@@ -22,6 +23,7 @@ local msvc-cxxs-with-experimental-fs = 14 ;
 project
   :
   requirements
+    <library>/boost/gil//boost_gil
     [ requires
         cxx14_constexpr
         cxx14_return_type_deduction

test/Jamfile

@@ -9,7 +9,8 @@
 # Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
 # http://www.boost.org/LICENSE_1_0.txt)
 
-import ../../config/checks/config : requires ;
+import-search /boost/config/checks ;
+import config : requires ;
 import os ;
 import path ;
 import regex ;
@@ -26,6 +27,7 @@ local msvc-cxxs-with-experimental-fs = 14 ;
 project
   :
   requirements
+    <library>/boost/gil//boost_gil
     [ requires
         cxx11_constexpr
         cxx11_defaulted_functions
@@ -83,21 +85,14 @@ rule generate_self_contained_headers ( headers_subpath * : exclude_subpaths * )
     # NOTE: All '/' in test names are replaced with '-' because apparently
     #       test scripts have a problem with test names containing slashes.
 
-    local top_headers_path = [ path.make $(BOOST_ROOT)/libs/gil/include/boost/gil ] ;
-    local headers_path = $(top_headers_path) ;
-    if $(headers_subpath)
-    {
-        headers_path = $(top_headers_path)/$(headers_subpath) ;
-    }
-
-    for local file in [ path.glob-tree $(headers_path) : *.hpp : $(exclude_subpaths) ]
+    for local file in [ glob-tree-ex ../include/boost/gil : *.hpp : $(exclude_subpaths) ]
     {
         local target_no = [ sequence.length $(targets) ] ;
-        local rel_file = [ path.relative-to $(top_headers_path) $(file) ] ;
+        local rel_file = [ path.relative-to ../include/boost/gil $(file) ] ;
         local target_name = [ regex.replace h/$(target_no)/$(rel_file) "/" "-" ] ;
         local target_name = [ regex.replace $(target_name) "\.hpp" "" ] ;
         targets += [
-            compile $(BOOST_ROOT)/libs/gil/test/header/main.cpp
+            compile header/main.cpp
             : <define>"BOOST_GIL_TEST_HEADER=$(rel_file)" <dependency>$(file)
             : $(target_name)
         ] ;

test/core/algorithm/Jamfile

@@ -10,6 +10,6 @@
 import testing ;
 
 run for_each_pixel.cpp ;
-run std_fill.cpp ;
+run std_fill.cpp : : : <library>/boost/array//boost_array ;
 run std_uninitialized_fill.cpp ;
 run extend_boundary.cpp ;

test/legacy/Jamfile

@@ -17,7 +17,7 @@
 
 import testing ;
 
-run image.cpp sample_image.cpp error_if.cpp : : gil_reference_checksums.txt ;
+run image.cpp sample_image.cpp error_if.cpp : : gil_reference_checksums.txt : <library>/boost/crc//boost_crc ;
 run channel.cpp error_if.cpp ;
 run pixel.cpp error_if.cpp ;
 run pixel_iterator.cpp error_if.cpp ;