Require at least boost 1.71

Author: anaegel

cmake/ug_includes.cmake

@@ -467,9 +467,11 @@ if(INTERNAL_BOOST)
 	set(INTERNAL_BOOST_PATH ${UG_ROOT_PATH}/externals/BoostForUG4/)
 	set(BOOST_ROOT ${INTERNAL_BOOST_PATH})
 	set(Boost_INCLUDE_DIRS ${INTERNAL_BOOST_PATH})
-	message(STATUS "Info: Internal Boost ${Boost_ADDITIONAL_VERSIONS}")
+	set(Boost_MAJOR_VERSION 1)
+	set(Boost_MINOR_VERSION 71)
+	message(STATUS "Info: Internal Boost ${Boost_MAJOR_VERSION}.${Boost_MINOR_VERSION}")
 else(INTERNAL_BOOST)
-	find_package(Boost 1.58 REQUIRED) # automatic detection
+	find_package(Boost 1.71 REQUIRED) # automatic detection
 
 	if(Boost_FOUND)
 		message(STATUS "Info: Found Boost ${Boost_VERSION} in <${Boost_INCLUDE_DIRS}>")