dnl --------------------------------------------------------------------------
dnl PA_ADD_CFLAGS()
dnl
dnl Attempt to add the given option to CFLAGS, if it doesn't break compilation
dnl --------------------------------------------------------------------------
AC_DEFUN(PA_ADD_CFLAGS,
[AC_MSG_CHECKING([if $CC accepts $1])
 pa_add_cflags__old_cflags="$CFLAGS"
 CFLAGS="$CFLAGS $1"
 AC_TRY_COMPILE([#include <stdio.h>],
 [printf("Hello, World!\n");],
 AC_MSG_RESULT([yes]),
 AC_MSG_RESULT([no])
 CFLAGS="$pa_add_cflags__old_cflags")])

dnl --------------------------------------------------------------------------
dnl PA_SIGSETJMP
dnl
dnl Do we have sigsetjmp/siglongjmp?  (AC_CHECK_FUNCS doesn't seem to work
dnl for these particular functions.)
dnl --------------------------------------------------------------------------
AC_DEFUN(PA_SIGSETJMP,
[AC_MSG_CHECKING([for sigsetjmp])
 AC_TRY_LINK(
 [#include <setjmp.h>],
 [sigjmp_buf buf;
  sigsetjmp(buf,1);
  siglongjmp(buf,2);],
 AC_MSG_RESULT([yes])
 $1,
 AC_MSG_RESULT([no])
 $2)])

dnl --------------------------------------------------------------------------
dnl PA_MSGHDR_MSG_CONTROL
dnl
dnl Does struct msghdr have the msg_control field?
dnl --------------------------------------------------------------------------
AC_DEFUN(PA_MSGHDR_MSG_CONTROL,
[AC_MSG_CHECKING([for msg_control in struct msghdr])
 AC_TRY_COMPILE(
[
#include <sys/types.h>
#include <sys/socket.h>
],
[
        struct msghdr msg;
        void *p = (void *) &msg.msg_control;
],
[
        AC_DEFINE(HAVE_MSGHDR_MSG_CONTROL)
        AC_MSG_RESULT([yes])
],
[
        AC_MSG_RESULT([no])
])])