Make work with missing commonTools/build_stats (trilinos#11976)

This is also a TriBITS Trilinos package so if it is not enabled, then it gets
excluded.  I am not sure this is the right thing to do but for now, it fixes
the immediate problem reported in trilinos#11976.

CMakeLists.txt

@@ -125,7 +125,9 @@ SET(${PROJECT_NAME}_ENABLE_EXPORT_MAKEFILES OFF CACHE BOOL
 # Do all of the processing for this Tribits project
 TRIBITS_PROJECT()
 
-INSTALL_BUILD_STATS_SCRIPTS()
+if (COMMAND INSTALL_BUILD_STATS_SCRIPTS)
+  INSTALL_BUILD_STATS_SCRIPTS()
+endif()
 
 # Install TriBITS so that other projects can use it.
 ADVANCED_SET(${PROJECT_NAME}_INSTALL_TriBITS ON CACHE BOOL

cmake/CallbackSetupExtraOptions.cmake

@@ -88,7 +88,12 @@ ENDMACRO()
 # Set up for build stats
 #
 
-include("${Trilinos_SOURCE_DIR}/commonTools/build_stats/BuildStatsWrappers.cmake")
-generate_build_stats_wrappers()
-remove_build_stats_file_on_configure()
-remove_build_stats_timing_files_on_fresh_configure()
+set(buildStatsWrappersFile
+  "${Trilinos_SOURCE_DIR}/commonTools/build_stats/BuildStatsWrappers.cmake")
+if (EXISTS "${buildStatsWrappersFile}")
+  include("${Trilinos_SOURCE_DIR}/commonTools/build_stats/BuildStatsWrappers.cmake")
+  generate_build_stats_wrappers()
+  remove_build_stats_file_on_configure()
+  remove_build_stats_timing_files_on_fresh_configure()
+endif()
+