diff --git a/generate4.xml b/generate4.xml
index 968f0e7..c463281 100644
--- a/generate4.xml
+++ b/generate4.xml
@@ -140,6 +140,7 @@
     <install>
       <!-- Boost.system is necessary for detection, which is only required for test. -->
       <build name="boost" version="1.78.0" parallel="true" nuget="true" prebuild="true" >
+        <flag value="-Wno-enum-constexpr-conversion" />
         <option value="--with-system" />
         <option value="--with-test" />
       </build>
@@ -482,6 +483,7 @@
         <option value="--disable-samples" />
       </build>
       <build name="boost" version="1.78.0" parallel="true" nuget="true" prebuild="true" >
+        <flag value="-Wno-enum-constexpr-conversion" />
         <option value="--with-chrono" />
         <option value="--with-iostreams" />
         <option value="--with-json" />
@@ -707,6 +709,7 @@
         <option value="--disable-samples" />
       </build>
       <build name="boost" version="1.78.0" parallel="true" nuget="true" prebuild="true" >
+        <flag value="-Wno-enum-constexpr-conversion" />
         <option value="--with-chrono" />
         <option value="--with-iostreams" />
         <option value="--with-json" />
diff --git a/templates/gsl.CMakeLists.txt b/templates/gsl.CMakeLists.txt
index c72b856..7c8db3c 100644
--- a/templates/gsl.CMakeLists.txt
+++ b/templates/gsl.CMakeLists.txt
@@ -34,15 +34,6 @@ function boost_component(name)
     endif
 endfunction
 
-function join_flags(container)
-    define my.container = join_flags.container
-    define my.result = ""
-    for my.container.flag as _flag where defined(_flag.name) & !is_empty(_flag.name)
-        my.result = join(my.result, "-$(_flag.name)", " ")
-    endfor
-    return my.result
-endfunction
-
 function get_cmake_system_from_name(name, sentinel)
     define my.result = my.sentinel
 
@@ -1107,7 +1098,7 @@ $(my.indent)$(my.name)( $(my.target_name)
 .   endif
 .
 .   define my.indent = defined(my.option) ?? "    " ? ""
-.   define my.flags = join_flags(my.compound)
+.   define my.flags = join_flags_name(my.compound)
 .   define my.symbol_prefix = defined(my.option) ?? "HAS_FLAGS_" ? my.define_prefix
 .
 .   if defined(my.option)
diff --git a/templates/gsl.configure.ac b/templates/gsl.configure.ac
index ff7aced..8eebb98 100644
--- a/templates/gsl.configure.ac
+++ b/templates/gsl.configure.ac
@@ -10,15 +10,6 @@
 # Functions
 ###############################################################################
 
-function join_flags(container)
-    define my.container = join_flags.container
-    define my.result = ""
-    for my.container.flag as _flag where defined(_flag.name) & !is_empty(_flag.name)
-        my.result = join(my.result, "-$(_flag.name)", " ")
-    endfor
-    return my.result
-endfunction
-
 function substitute_system_include(variable_name)
     return "`echo ${$(my.variable_name)} | $SED s/^-I/-isystem/g | $SED s/' -I'/' -isystem'/g`"
 endfunction
@@ -1022,7 +1013,7 @@ AC_MSG_NOTICE([$(my.cname)_BUILD_CPPFLAGS : ${$(my.cname)_BUILD_CPPFLAGS}])
 .   endif
 .
 .   define my.indent = defined(my.option) ?? "    " ? ""
-.   define my.flags = join_flags(my.compound)
+.   define my.flags = join_flags_name(my.compound)
 .   define my.terminator = "])"
 .
 .   if defined(my.option)
diff --git a/templates/shared/common_install_shell_artifacts.gsl b/templates/shared/common_install_shell_artifacts.gsl
index f69b18e..d46ff51 100644
--- a/templates/shared/common_install_shell_artifacts.gsl
+++ b/templates/shared/common_install_shell_artifacts.gsl
@@ -1105,14 +1105,29 @@ build_from_tarball_boost()
 
     initialize_boost_configuration
     initialize_boost_icu_configuration
+.
+.   if (defined(my.build.prebuild))
+
+    guessed_toolset=`./tools/build/src/engine/build.sh --guess-toolset`
+    CXXFLAGS="-w" ./tools/build/src/engine/build.sh ${guessed_toolset} --cxxflags="-w"
+    cp tools/build/src/engine/b2 .
+.   endif
+.
+.   if (count(my.build.flag) > 0)
+    if [[ (x"$BOOST_CXXFLAGS" == "x") ]]; then
+        BOOST_CXXFLAGS="cxxflags=${BOOST_FLAGS[@]}"
+    else
+        BOOST_CXXFLAGS="$BOOST_CXXFLAGS ${BOOST_FLAGS[@]}"
+    fi
+.   endif
 
     display_message "Libbitcoin boost configuration."
     display_message "--------------------------------------------------------------------"
     display_message "variant               : release"
     display_message "threading             : multi"
     display_message "toolset               : $CC"
-    display_message "cxxflags              : $STDLIB_FLAG"
-    display_message "linkflags             : $STDLIB_FLAG"
+    display_message "boost cxxflags        : $BOOST_CXXFLAGS"
+    display_message "boost linkflags       : $BOOST_LINKFLAGS"
     display_message "link                  : $BOOST_LINK"
     display_message "boost.locale.iconv    : $BOOST_ICU_ICONV"
     display_message "boost.locale.posix    : $BOOST_ICU_POSIX"
@@ -1126,15 +1141,9 @@ build_from_tarball_boost()
     display_message "--reconfigure         : [ignore cached configuration]"
     display_message "--prefix              : $PREFIX"
     display_message "BOOST_OPTIONS         : $*"
+    display_message "cxxflags (ignored)    : $CXXFLAGS"
     display_message "--------------------------------------------------------------------"
 
-.
-.   if (defined(my.build.prebuild))
-    guessed_toolset=`./tools/build/src/engine/build.sh --guess-toolset`
-    CXXFLAGS="-w" ./tools/build/src/engine/build.sh ${guessed_toolset} --cxxflags="-w"
-    cp tools/build/src/engine/b2 .
-
-.   endif
     ./bootstrap.sh \\
 .   if (defined(my.build.prebuild))
         "--with-bjam=./b2" \\
diff --git a/utilities.gsl b/utilities.gsl
index 5fab5e1..9605863 100644
--- a/utilities.gsl
+++ b/utilities.gsl
@@ -113,6 +113,24 @@ endfunction
 # Library utilities.
 #------------------------------------------------------------------------------
 
+function global.join_flags_name(container)
+    define my.container = join_flags_name.container
+    define my.result = ""
+    for my.container.flag as _flag where defined(_flag.name) & !is_empty(_flag.name)
+        my.result = join(my.result, "-$(_flag.name)", " ")
+    endfor
+    return my.result
+endfunction
+
+function global.join_flags_value(container)
+    define my.container = join_flags_value.container
+    define my.result = ""
+    for my.container.flag as _flag where defined(_flag.value) & !is_empty(_flag.value)
+        my.result = join(my.result, "$(_flag.value)", " ")
+    endfor
+    return my.result
+endfunction
+
 function global.canonical_path_name(repository)
     define my.repository = canonical_path_name.repository
     return defined(my.repository.path) ?? my.repository.path ?\