COMP: Fix build against non-standard outside libarchive

Use the include directories reported by find_package(LibArchive).

CMakeLists.txt

@@ -325,6 +325,7 @@ MACRO (CMAKE_BUILD_UTILITIES)
     IF(NOT LibArchive_FOUND)
       MESSAGE(FATAL_ERROR "CMAKE_USE_SYSTEM_LIBARCHIVE is ON but LibArchive is not found!")
     ENDIF()
+    SET(CMAKE_TAR_INCLUDES ${LibArchive_INCLUDE_DIRS})
     SET(CMAKE_TAR_LIBRARIES ${LibArchive_LIBRARIES})
   ELSE(CMAKE_USE_SYSTEM_LIBARCHIVE)
     SET(HAVE_LIBZ 1)