boost fixes

cmake/libraries/boost.cmake

@@ -94,28 +94,28 @@ if(PROJECT_ENABLE_BOOST)
         set(BOOST_LINK "static,shared")
       endif()
 
+      if(PROJECT_ENABLE_LIBBITCOIN_SYSTEM)
+        set(BOOST_CXX_STANDARD 20)
+      else()
+        set(BOOST_CXX_STANDARD ${CMAKE_CXX_STANDARD})
+      endif()
+
       set(BOOST_BUILD_ARGS
         --openssldir=$ENV{OPENSSL_ROOT_DIR}
         --prefix=${PROJECT_EXTERNAL_BUILD_ROOT}
         address-model=64
         architecture=${BOOST_ARCH}
         cxxstd-dialect=gnu
-        cxxflags=-std=gnu++${CMAKE_CXX_STANDARD}
-        cxxstd=${CMAKE_CXX_STANDARD}
+        cxxflags=-std=gnu++${BOOST_CXX_STANDARD}
+        cxxstd=${BOOST_CXX_STANDARD}
         define=BOOST_ASIO_HAS_STD_STRING_VIEW
         define=BOOST_SYSTEM_NO_DEPRECATED
         link=${BOOST_LINK}
-        linkflags=-std=gnu++${CMAKE_CXX_STANDARD}
+        linkflags=-std=gnu++${BOOST_CXX_STANDARD}
         threading=multi
         variant=${BOOST_BUILD_TYPE_LOWER}
       )
 
-      if(PROJECT_ENABLE_LIBBITCOIN_SYSTEM)
-        set(BOOST_URL_HASH SHA256=${BOOST2_HASH})
-      else()
-        set(BOOST_URL_HASH SHA256=${BOOST_HASH})
-      endif()
-
       ExternalProject_Add(boost_project
         PREFIX external
         URL ${PROJECT_3RD_PARTY_DIR}/boost_${BOOST_MAJOR_VERSION}_${BOOST_MINOR_VERSION}_${BOOST_PATCH_VERSION}.tar.gz