dnl GNUPG_CHECK_TYPEDEF(TYPE, HAVE_NAME)
dnl Check whether a typedef exists and create a #define $2 if it exists
dnl
AC_DEFUN(GNUPG_CHECK_TYPEDEF,
  [ AC_MSG_CHECKING(for $1 typedef)
    AC_CACHE_VAL(gnupg_cv_typedef_$1,
    [AC_TRY_COMPILE([#include <stdlib.h>
    #include <sys/types.h>], [
    #undef $1
    int a = sizeof($1);
    ], gnupg_cv_typedef_$1=yes, gnupg_cv_typedef_$1=no )])
    AC_MSG_RESULT($gnupg_cv_typedef_$1)
    if test "$gnupg_cv_typedef_$1" = yes; then
        AC_DEFINE($2)
    fi
  ])