dnl Macros to check the presence of generic (non-typed) symbols.
dnl Copyright (c) 2007 xine project
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dnl AC_CHECK_SYMBOL - Check for a single symbol
dnl Usage: AC_CHECK_SYMBOL([symbol], [action-if-found], [action-if-not-found])
dnl Default action, defines HAVE_SYMBOL (with symbol capitalised) if the
dnl symbol is present at link time.
AC_DEFUN([AC_CHECK_SYMBOL], [
  AC_CACHE_CHECK([for $1 symbol presence],
    AS_TR_SH([ac_cv_symbol_$1]),
    [AC_TRY_LINK([extern void *$1;], [void *tmp = $1;],
       [eval "AS_TR_SH([ac_cv_symbol_$1])=yes"],
       [eval "AS_TR_SH([ac_cv_symbol_$1])=no"])
    ])

  if eval test [x$]AS_TR_SH([ac_cv_symbol_$1]) = xyes; then
    ifelse([$2], , [AC_DEFINE_UNQUOTED(AS_TR_CPP([HAVE_$1]), [1],
      [Define to 1 if you have the $1 symbol.])], [$2])
  else
    ifelse([$3], , [:], [$3])
  fi
])

dnl AC_CHECK_SYMBOLS - Check for multiple symbols
dnl Usage: AC_CHECK_SYMBOLS([symbol1 symbol2], [action-if-found], [action-if-not-found])
AC_DEFUN([AC_CHECK_SYMBOLS], [
  AH_CHECK_SYMBOLS([$1])

  for ac_symbol in $1
  do
    AC_CHECK_SYMBOL($ac_symbol, [AC_DEFINE_UNQUOTED(AS_TR_CPP([HAVE_$ac_symbol])) $2], [$3])
  done
])

m4_ifdef([m4_foreach_w], [], [
  # m4_foreach_w(VARIABLE, LIST, EXPRESSION)
  # ----------------------------------------
  #
  # Like m4_foreach, but the list is whitespace separated.
  #
  # This macro is robust to active symbols:
  #    m4_foreach_w([Var], [ active
  #    b	act\
  #    ive  ], [-Var-])end
  #    => -active--b--active-end
  #
  m4_define([m4_foreach_w],
  [m4_foreach([$1], m4_split(m4_normalize([$2])), [$3])])
  m4_define([m4_foreach_w_is_compatibility])
])

m4_define([AH_CHECK_SYMBOLS], [
  m4_foreach_w([AC_Symbol], [$1],
   [AH_TEMPLATE(AS_TR_CPP([HAVE_]m4_defn([AC_Symbol])),
      [Define to 1 if you have the ]m4_defn([AC_Symbol])[ symbol.])])
])