Merge branch 'upstream-libxml2' into update-libxml2

* upstream-libxml2:
  libxml2 2019-04-01 (a41ab7b3)

Author: cquammen

ThirdParty/libxml2/vtklibxml2/CMakeLists.txt

@@ -4,6 +4,12 @@ SET(LIBXML_VERSION_NUMBER 20627)
 SET(LIBXML_VERSION_EXTRA "")
 SET(MODULE_EXTENSION ${CMAKE_SHARED_MODULE_SUFFIX})
 
+# Use new behavior of linking against libraries in the CMAKE_REQUIRED_LIBRARIES
+# variable in the CHECK_INCLUDE_FILE macro
+IF (POLICY CMP0075)
+  CMAKE_POLICY(SET CMP0075 NEW)
+ENDIF()
+
 INCLUDE(CheckLibraryExists)
 INCLUDE(CheckIncludeFile)
 INCLUDE(CheckIncludeFiles)