Add support for Boost_PYTHON_VERSION_MAJOR

BoostConfig.cmake

@@ -120,6 +120,13 @@ macro(boost_find_component comp req)
     set(Boost_PYTHON_VERSION "${CMAKE_MATCH_2}.${CMAKE_MATCH_3}")
     set(__boost_comp_nv "${CMAKE_MATCH_1}")
 
+  elseif("${comp}" MATCHES "^(python|numpy|mpi_python)([1-9])$")
+
+    # handle python2/python3 for compatibility
+
+    set(Boost_PYTHON_VERSION_MAJOR "${CMAKE_MATCH_2}")
+    set(__boost_comp_nv "${CMAKE_MATCH_1}")
+
   else()
 
     set(__boost_comp_nv "${comp}")

boost-install.jam

@@ -151,6 +151,13 @@ rule generate-cmake-variant- ( target : sources * : properties * )
             "  endif()"
             "endif()"
             ""
+            "if(Boost_PYTHON_VERSION_MAJOR)"
+            "  if(NOT \"$(python)\" MATCHES \"^${Boost_PYTHON_VERSION_MAJOR}[.]\")"
+            "    _BOOST_SKIPPED(\"$(fname)\" \"$(python), Boost_PYTHON_VERSION_MAJOR=${Boost_PYTHON_VERSION_MAJOR}\")"
+            "    return()"
+            "  endif()"
+            "endif()"
+            ""
             : true ;
     }