Make TriBITS package TribitsExampleProject/Package1 work with 100% ra…

…w CMake (TriBITSPub#582)

This raw CMake build mode for Package1 uses no TriBITS macros, functions, or
other functionality at all.

The only change to TriBITS-proper were:

* Skip check for not calling tribits_package_postprocess() if the
  `<Package>::all_libs` target is already defined.

* Build up the list of package libraries target for the `<Project>_libs`
  target from `<Package>::all_libs` instead of `<Package>_libs`.

This seems to pass all of the TriBITS tests.

tribits/examples/TribitsExampleProject2/packages/package1/CMakeLists.txt

@@ -39,8 +39,8 @@ else()
   target_link_libraries(Package1_all_libs INTERFACE Package1_package1)
   install(TARGETS Package1_all_libs
     EXPORT ${PROJECT_NAME}
-    INCLUDES DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
-    COMPONENT ${PROJECT_NAME} )
+    COMPONENT ${PROJECT_NAME}
+    INCLUDES DESTINATION ${CMAKE_INSTALL_INCLUDEDIR} )
   add_library(Package1::all_libs ALIAS Package1_all_libs)
 
   # Generate Package1Config.cmake file for the build tree