build: consolidate reduced export checks

configure.ac

@@ -1191,12 +1191,6 @@ AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
  [ AC_MSG_RESULT(no); HAVE_WEAK_GETAUXVAL=0 ]
 )
 
-dnl Check for reduced exports
-if test x$use_reduce_exports = xyes; then
-  AX_CHECK_COMPILE_FLAG([-fvisibility=hidden],[RE_CXXFLAGS="-fvisibility=hidden"],
-  [AC_MSG_ERROR([Cannot set default symbol visibility. Use --disable-reduce-exports.])])
-fi
-
 AC_MSG_CHECKING([for std::system])
 AC_LINK_IFELSE(
     [ AC_LANG_PROGRAM(
@@ -1410,9 +1404,11 @@ BOOST_CPPFLAGS="-DBOOST_SP_USE_STD_ATOMIC -DBOOST_AC_USE_STD_ATOMIC $BOOST_CPPFL
 BOOST_LIBS="$BOOST_LDFLAGS $BOOST_SYSTEM_LIB $BOOST_FILESYSTEM_LIB $BOOST_THREAD_LIB"
 fi
 
+dnl Check for reduced exports
 if test x$use_reduce_exports = xyes; then
-    CXXFLAGS="$CXXFLAGS $RE_CXXFLAGS"
-    AX_CHECK_LINK_FLAG([[-Wl,--exclude-libs,ALL]], [RELDFLAGS="-Wl,--exclude-libs,ALL"],, [[$LDFLAG_WERROR]])
+    AX_CHECK_COMPILE_FLAG([-fvisibility=hidden],[CXXFLAGS="$CXXFLAGS -fvisibility=hidden"],
+    [AC_MSG_ERROR([Cannot set hidden symbol visibility. Use --disable-reduce-exports.])],[[$CXXFLAG_WERROR]])
+    AX_CHECK_LINK_FLAG([[-Wl,--exclude-libs,ALL]],[RELDFLAGS="-Wl,--exclude-libs,ALL"],,[[$LDFLAG_WERROR]])
 fi
 
 if test x$use_tests = xyes; then