+### use option --enable-fvisibility to turn on use of gcc-specific feature
+AC_MSG_CHECKING(if you want to use gcc -fvisibility option)
+AC_ARG_ENABLE(fvisibility,
+ [ --enable-fvisibility compile with -fvisibility=hidden],
+ [cf_with_fvisibility=$enableval],
+ [cf_with_fvisibility=no])
+AC_MSG_RESULT($cf_with_fvisibility)
+
+NCURSES_IMPEXP=
+NCURSES_CXX_IMPEXP=
+if test "x$cf_with_fvisibility" = xyes; then
+ CF_CHECK_FVISIBILITY($CC,CFLAGS,cf_cv_fvisibility_hidden)
+ if test "x$cf_cv_fvisibility_hidden" = xyes
+ then
+ CF_ADD_CFLAGS([-fvisibility=hidden])
+ NCURSES_IMPEXP="__attribute__ ((visibility(\"default\")))"
+ fi
+ if test -n "$CXX"
+ then
+ AC_LANG_PUSH(C++)
+ CF_CHECK_FVISIBILITY($CXX,CXXFLAGS,cf_cv_fvisibility_hidden2)
+ if test "x$cf_cv_fvisibility_hidden2" = xyes
+ then
+ CF_ADD_CXXFLAGS([-fvisibility=hidden])
+ NCURSES_CXX_IMPEXP="__attribute__ ((visibility(\"default\")))"
+ fi
+ AC_LANG_POP
+ fi
+fi
+AC_SUBST(NCURSES_IMPEXP)
+AC_SUBST(NCURSES_CXX_IMPEXP)
+