message: Fix build for automake 1.16.5
  Summary:
  Pull Request resolved:
  As title
diff: AC_PREREQ([2.69])
  AC_INIT([redex], [1.0], [not-valid-yet@fb.com])
  -AM_INIT_AUTOMAKE(redex, 1.0)
  -
  +AM_INIT_AUTOMAKE([subdir-objects])
  # clear out default cxx flags (was "-O2 -g") so that they don't override
  # the flags defined in AM_CXXFLAGS
  : ${CXXFLAGS=""}
  @@ -15,8 +14,6 @@ AC_PROG_CC
  LT_INIT
  -AM_INIT_AUTOMAKE([subdir-objects])
  -
  AC_CONFIG_MACRO_DIR([m4])
  AM_PATH_PYTHON([3.0], [], [AC_MSG_ERROR([Redex requires python3])])
  