Move inter-lib dependencies to a project variable and into the build …

…targets.

build.jam

@@ -11,15 +11,17 @@ require-b2 5.2 ;
 #   Test without exceptions and rtti:  b2 cxxstd=latest exception-handling=off rtti=off test//minimal
 #   Test with sanitizers:              b2 toolset=clang cxxstd=latest histogram_ubasan test
 
+constant boost_dependencies :
+    /boost/config//boost_config
+    /boost/core//boost_core
+    /boost/math//boost_math
+    /boost/mp11//boost_mp11
+    /boost/serialization//boost_serialization
+    /boost/throw_exception//boost_throw_exception
+    /boost/variant2//boost_variant2 ;
+
 project /boost/histogram
     : common-requirements
-        <library>/boost/config//boost_config
-        <library>/boost/core//boost_core
-        <library>/boost/math//boost_math
-        <library>/boost/mp11//boost_mp11
-        <library>/boost/serialization//boost_serialization
-        <library>/boost/throw_exception//boost_throw_exception
-        <library>/boost/variant2//boost_variant2
         <include>include
     : requirements
         <toolset>clang:<cxxflags>"-Wsign-compare -Wstrict-aliasing -fstrict-aliasing -Wvexing-parse -Wfloat-conversion"
@@ -33,7 +35,7 @@ project /boost/histogram
     ;
 
 explicit
-    [ alias boost_histogram ]
+    [ alias boost_histogram : : : : <library>$(boost_dependencies) ]
     [ alias all : boost_histogram test examples ]
     ;
 
@@ -47,3 +49,4 @@ variant histogram_ubasan : debug :
     <cxxflags>"-fno-omit-frame-pointer -O0 -fno-inline -fsanitize=address,leak,undefined -fno-sanitize-recover=all -fsanitize-blacklist=$(THIS_PATH)/tools/blacklist.supp"
     <linkflags>"-fsanitize=address,leak,undefined"
     ;
+