;;
darwin*)
CXXFLAGS="-D__APPLE_USE_RFC_3542 -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE $CXXFLAGS"
+ have_darwin="yes"
;;
freebsd*)
THREADFLAGS="-pthread"
AM_CONDITIONAL([HAVE_FREEBSD], [test "x$have_freebsd" = "xyes"])
AM_CONDITIONAL([HAVE_OPENBSD], [test "x$have_openbsd" = "xyes"])
AM_CONDITIONAL([HAVE_LINUX], [test "x$have_linux" = "xyes"])
+ AM_CONDITIONAL([HAVE_DARWIN], [test "x$have_darwin" = "xyes"])
AM_CONDITIONAL([HAVE_SOLARIS], [test "x$have_solaris" = "xyes"])
AC_MSG_CHECKING([whether -latomic is needed for __atomic builtins])