FindBoost: Add checks for component-specific headers

This supplements the existing library checks, to
cater for the possibility that the libraries are
present but the headers are not.  This can happen
when the Boost collections is split up into
multiple packages and not all are installed,
and will avoid the checks silently passing when
the build would subsequently fail.

Modules/FindBoost.cmake

@@ -310,7 +310,7 @@ macro(_Boost_ADJUST_LIB_VARS basename)
       set(Boost_${basename}_LIBRARIES ${Boost_${basename}_LIBRARY_RELEASE} )
     endif()
 
-    if(Boost_${basename}_LIBRARY)
+    if(Boost_${basename}_LIBRARY AND Boost_${basename}_HEADER)
       set(Boost_${basename}_FOUND ON)
     endif()
 
@@ -522,7 +522,9 @@ function(_Boost_COMPONENT_DEPENDENCIES component _ret)
   #
   # The output may be added in a new block below.  If it's the same as
   # the previous release, simply update the version range of the block
-  # for the previous release.
+  # for the previous release.  Also check if any new components have
+  # been added, and add any new components to
+  # _Boost_COMPONENT_HEADERS.
   #
   # This information was originally generated by running
   # BoostScanDeps.cmake against every boost release to date supported
@@ -739,6 +741,67 @@ function(_Boost_COMPONENT_DEPENDENCIES component _ret)
   # message(STATUS "Dependencies for Boost::${component}: ${_boost_DEPS_STRING}")
 endfunction()
 
+#
+# Get component headers.  This is the primary header (or headers) for
+# a given component, and is used to check that the headers are present
+# as well as the library itself as an extra sanity check of the build
+# environment.
+#
+# component - the component to check
+# _hdrs
+#
+function(_Boost_COMPONENT_HEADERS component _hdrs)
+  # Note: new boost components will require adding here.  The header
+  # must be present in all versions of Boost providing a library.
+  set(_Boost_ATOMIC_HEADERS              "boost/atomic.hpp")
+  set(_Boost_CHRONO_HEADERS              "boost/chrono.hpp")
+  set(_Boost_CONTAINER_HEADERS           "boost/container/container_fwd.hpp")
+  set(_Boost_CONTEXT_HEADERS             "boost/context/all.hpp")
+  set(_Boost_COROUTINE_HEADERS           "boost/coroutine/all.hpp")
+  set(_Boost_EXCEPTION_HEADERS           "boost/exception/exception.hpp")
+  set(_Boost_DATE_TIME_HEADERS           "boost/date_time/date.hpp")
+  set(_Boost_FILESYSTEM_HEADERS          "boost/filesystem/path.hpp")
+  set(_Boost_GRAPH_HEADERS               "boost/graph/adjacency_list.hpp")
+  set(_Boost_GRAPH_PARALLEL_HEADERS      "boost/graph/adjacency_list.hpp")
+  set(_Boost_IOSTREAMS_HEADERS           "boost/iostreams/stream.hpp")
+  set(_Boost_LOCALE_HEADERS              "boost/locale.hpp")
+  set(_Boost_LOG_HEADERS                 "boost/log/core.hpp")
+  set(_Boost_LOG_SETUP_HEADERS           "boost/log/detail/setup_config.hpp")
+  set(_Boost_MATH_HEADERS                "boost/math_fwd.hpp")
+  set(_Boost_MATH_C99_HEADERS            "boost/math/tr1.hpp")
+  set(_Boost_MATH_C99F_HEADERS           "boost/math/tr1.hpp")
+  set(_Boost_MATH_C99L_HEADERS           "boost/math/tr1.hpp")
+  set(_Boost_MATH_TR1_HEADERS            "boost/math/tr1.hpp")
+  set(_Boost_MATH_TR1F_HEADERS           "boost/math/tr1.hpp")
+  set(_Boost_MATH_TR1L_HEADERS           "boost/math/tr1.hpp")
+  set(_Boost_MPI_HEADERS                 "boost/mpi.hpp")
+  set(_Boost_MPI_PYTHON_HEADERS          "boost/mpi/python/config.hpp")
+  set(_Boost_PRG_EXEC_MONITOR_HEADERS    "boost/test/prg_exec_monitor.hpp")
+  set(_Boost_PROGRAM_OPTIONS_HEADERS     "boost/program_options.hpp")
+  set(_Boost_PYTHON_HEADERS              "boost/python.hpp")
+  set(_Boost_RANDOM_HEADERS              "boost/random.hpp")
+  set(_Boost_REGEX_HEADERS               "boost/regex.hpp")
+  set(_Boost_SERIALIZATION_HEADERS       "boost/serialization/serialization.hpp")
+  set(_Boost_SIGNALS_HEADERS             "boost/signals.hpp")
+  set(_Boost_SYSTEM_HEADERS              "boost/system/config.hpp")
+  set(_Boost_TEST_EXEC_MONITOR_HEADERS   "boost/test/test_exec_monitor.hpp")
+  set(_Boost_THREAD_HEADERS              "boost/thread.hpp")
+  set(_Boost_TIMER_HEADERS               "boost/timer.hpp")
+  set(_Boost_TYPE_ERASURE_HEADERS        "boost/type_erasure/config.hpp")
+  set(_Boost_UNIT_TEST_FRAMEWORK_HEADERS "boost/test/framework.hpp")
+  set(_Boost_WAVE_HEADERS                "boost/wave.hpp")
+  set(_Boost_WSERIALIZATION_HEADERS      "boost/archive/text_wiarchive.hpp")
+
+  string(TOUPPER ${component} uppercomponent)
+  set(${_hdrs} ${_Boost_${uppercomponent}_HEADERS} PARENT_SCOPE)
+
+  string(REGEX REPLACE ";" " " _boost_HDRS_STRING "${_Boost_${uppercomponent}_HEADERS}")
+  if (NOT _boost_HDRS_STRING)
+    set(_boost_HDRS_STRING "(none)")
+  endif()
+  # message(STATUS "Headers for Boost::${component}: ${_boost_HDRS_STRING}")
+endfunction()
+
 #
 # Determine if any missing dependencies require adding to the component list.
 #
@@ -826,8 +889,9 @@ else()
   # versions, find those that are acceptable to the user request.
   #
   # Note: When adding a new Boost release, also update the dependency
-  # information in _Boost_COMPONENT_DEPENDENCIES.  See the
-  # instructions at the top of _Boost_COMPONENT_DEPENDENCIES.
+  # information in _Boost_COMPONENT_DEPENDENCIES and
+  # _Boost_COMPONENT_HEADERS.  See the instructions at the top of
+  # _Boost_COMPONENT_DEPENDENCIES.
   set(_Boost_KNOWN_VERSIONS ${Boost_ADDITIONAL_VERSIONS}
     "1.61.0" "1.61" "1.60.0" "1.60"
     "1.59.0" "1.59" "1.58.0" "1.58" "1.57.0" "1.57" "1.56.0" "1.56" "1.55.0" "1.55"
@@ -1365,6 +1429,22 @@ foreach(COMPONENT ${Boost_FIND_COMPONENTS})
     endif()
   endif()
 
+  #
+  # Find headers
+  #
+  _Boost_COMPONENT_HEADERS("${COMPONENT}" Boost_${UPPERCOMPONENT}_HEADER_NAME)
+  # Look for a standard boost header file.
+  if(Boost_${UPPERCOMPONENT}_HEADER_NAME)
+    if(EXISTS "${Boost_INCLUDE_DIR}/${Boost_${UPPERCOMPONENT}_HEADER_NAME}")
+      set(Boost_${UPPERCOMPONENT}_HEADER ON)
+    else()
+      set(Boost_${UPPERCOMPONENT}_HEADER OFF)
+    endif()
+  else()
+    set(Boost_${UPPERCOMPONENT}_HEADER ON)
+    message(WARNING "No header defined for ${COMPONENT}; skipping header check")
+  endif()
+
   #
   # Find RELEASE libraries
   #