get_property(EXISTS GLOBAL PROPERTY _LIBXML2_INCLUDED)
if(EXISTS)
    return()
endif()
#
# libxml2
#

find_package(LibXml2)
set_package_properties(LibXml2 PROPERTIES TYPE OPTIONAL)
mark_as_advanced(CLEAR LIBXML2_INCLUDE_DIR)
mark_as_advanced(CLEAR LIBXML2_LIBRARIES)
if (LIBXML2_FOUND)
    set(PDAL_HAVE_LIBXML2 1)
else()
    unset(LIBXML2_INCLUDE_DIR CACHE)
    unset(LIBXML2_LIBRARY CACHE)
    unset(LIBXML2_XMLLINT_EXECUTABLE CACHE)
    unset(LIBXML2_LIBRARIES) # Find-module output variable, not cache variable
endif()

set_property(GLOBAL PROPERTY _LIBXML2_INCLUDED TRUE)