configure.in

dnl $Id$
dnl Copyright (c) 2001-2004, Roger Dingledine
dnl Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson
dnl Copyright (c) 2007-2008, The Tor Project, Inc.
dnl See LICENSE for licensing information

AC_INIT
AM_INIT_AUTOMAKE(tor, 0.2.1.4-alpha-dev)
AM_CONFIG_HEADER(orconfig.h)

AC_CANONICAL_HOST

if test -f /etc/redhat-release ; then
  if test -f /usr/kerberos/include ; then
    CPPFLAGS="$CPPFLAGS -I/usr/kerberos/include"
  fi
fi

# Not a no-op; we want to make sure that CPPFLAGS is set before we use
# the += operator on it in src/or/Makefile.am
CPPFLAGS="$CPPFLAGS -I../common"

AC_ARG_ENABLE(debug,
 AS_HELP_STRING(--enable-debug, compile with debugging info),
[if test x$enableval = xyes; then
    CFLAGS="$CFLAGS -g"
fi])

#XXXX ideally, we should make this into a no-op, and detect whether we're
#compiling for the iphone by using $target.
AC_ARG_ENABLE(iphone,
 AS_HELP_STRING(--enable-iphone, compile with iPhone support),
 [if test x$enableval = xyes ; then
   tor_cv_iphone=true
   CFLAGS="$CFLAGS -D__DARWIN_UNIX03 -DIPHONE"
  fi])

#XXXX020 We should make these enabled or not, before 0.2.0.x-final
AC_ARG_ENABLE(cell-pool,
     AS_HELP_STRING(--disable-cell-pool, disable pool allocator for cells))
AC_ARG_ENABLE(buf-freelists,
   AS_HELP_STRING(--disable-buf-freelists, disable freelists for buffer RAM))
AC_ARG_ENABLE(openbsd-malloc,
   AS_HELP_STRING(--enable-openbsd-malloc, Use malloc code from openbsd.  Linux only))
AC_ARG_ENABLE(instrument-downloads,
   AS_HELP_STRING(--enable-instrument-downloads, Instrument downloads of directory resources etc.))


if test x$enable_cell_pool != xno; then
  AC_DEFINE(ENABLE_CELL_POOL, 1,
            [Defined if we try to use the pool allocator for queued cells])
fi
if test x$enable_buf_freelists != xno; then
  AC_DEFINE(ENABLE_BUF_FREELISTS, 1,
            [Defined if we try to use freelists for buffer RAM chunks])
fi
AM_CONDITIONAL(USE_OPENBSD_MALLOC, test x$enable_openbsd_malloc = xyes)
if test x$enable_instrument_downloads == xyes; then
  AC_DEFINE(INSTRUMENT_DOWNLOADS, 1,
            [Defined if we want to keep track of how much of each kind of resource we download.])
fi

AC_ARG_ENABLE(transparent,
     AS_HELP_STRING(--disable-transparent, disable transparent proxy support),
     [case "${enableval}" in
        yes) transparent=true ;;
        no)  transparent=false ;;
        *) AC_MSG_ERROR(bad value for --enable-transparent) ;;
      esac], [transparent=true])

AC_ARG_ENABLE(threads,
     AS_HELP_STRING(--disable-threads, disable multi-threading support))

if test x$enable_threads = x; then
   case $host in
    *-*-solaris* )
     # Don't try multithreading on solaris -- cpuworkers seem to lock.
     AC_MSG_NOTICE([You are running Solaris; Sometimes threading makes
cpu workers lock up here, so I will disable threads.])
     enable_threads="no";;
    *)
     enable_threads="yes";;
   esac
fi

if test "$enable_threads" = "yes"; then
  AC_DEFINE(ENABLE_THREADS, 1, [Defined if we will try to use multithreading])
fi

case $host in
   *-*-solaris* )
     AC_DEFINE(_REENTRANT, 1, [Define on some platforms to activate x_r() functions in time.h])
     ;;
esac

AC_ARG_ENABLE(geoip-stats,
     AS_HELP_STRING(--enable-geoip-stats, enable code for directories to collect per-country statistics))

if test "$enable_geoip_stats" = "yes"; then
  AC_DEFINE(ENABLE_GEOIP_STATS, 1, [Defined if we try to collect per-country statistics])
fi

AC_ARG_ENABLE(gcc-warnings,
     AS_HELP_STRING(--enable-gcc-warnings, enable verbose warnings))

AC_PROG_CC
AC_PROG_CPP
AC_PROG_MAKE_SET
AC_PROG_RANLIB

TORUSER=_tor
AC_ARG_WITH(tor-user,
        [  --with-tor-user=NAME    Specify username for tor daemon ],
        [
           TORUSER=$withval
        ]
)
AC_SUBST(TORUSER)

TORGROUP=_tor
AC_ARG_WITH(tor-group,
        [  --with-tor-group=NAME   Specify group name for tor daemon ],
        [
           TORGROUP=$withval
        ]
)
AC_SUBST(TORGROUP)


dnl If WIN32 is defined and non-zero, we are building for win32
AC_MSG_CHECKING([for win32])
AC_RUN_IFELSE([
int main(int c, char **v) {
#ifdef WIN32
#if WIN32
  return 0;
#else
  return 1;
#endif
#else
  return 2;
#endif
}],
bwin32=true; AC_MSG_RESULT([yes]),
bwin32=false; AC_MSG_RESULT([no]),
bwin32=cross; AC_MSG_RESULT([cross])
)

if test "$bwin32" = cross; then
AC_MSG_CHECKING([for win32 (cross)])
AC_COMPILE_IFELSE([
#ifdef WIN32
int main(int c, char **v) {return 0;}
#else
#error
int main(int c, char **v) {return x(y);}
#endif
],
bwin32=true; AC_MSG_RESULT([yes]),
bwin32=false; AC_MSG_RESULT([no]))
fi

if test "$bwin32" = true; then
AC_DEFINE(MS_WINDOWS, 1, [Define to 1 if we are building for Windows.])
fi
AM_CONDITIONAL(BUILD_NT_SERVICES, test x$bwin32 = xtrue)

dnl Enable C99 when compiling with MIPSpro
AC_MSG_CHECKING([for MIPSpro compiler])
AC_COMPILE_IFELSE(AC_LANG_PROGRAM(, [
#if (defined(__sgi) && defined(_COMPILER_VERSION))
#error
  return x(y);
#endif
]),
bmipspro=false; AC_MSG_RESULT(no),
bmipspro=true; AC_MSG_RESULT(yes))

if test "$bmipspro" = true; then
  CFLAGS="$CFLAGS -c99"
fi

AC_C_BIGENDIAN

AC_SEARCH_LIBS(socket, [socket])
AC_SEARCH_LIBS(gethostbyname, [nsl])
AC_SEARCH_LIBS(dlopen, [dl])
AC_SEARCH_LIBS(inet_aton, [resolv])

if test "$enable_threads" = "yes"; then
  AC_SEARCH_LIBS(pthread_create, [pthread])
  AC_SEARCH_LIBS(pthread_detach, [pthread])
fi

dnl -------------------------------------------------------------------
dnl Check for functions before libevent, since libevent-1.2 apparently
dnl exports strlcpy without defining it in a header.

AC_CHECK_FUNCS(gettimeofday ftime socketpair uname inet_aton strptime getrlimit strlcat strlcpy strtoull ftello getaddrinfo localtime_r gmtime_r memmem strtok_r inet_pton inet_ntop writev readv)

using_custom_malloc=no
if test x$enable_openbsd_malloc = xyes ; then
   AC_DEFINE(HAVE_MALLOC_GOOD_SIZE, 1, [Defined if we have the malloc_good_size function])
   using_custom_malloc=yes
fi
if test x$tcmalloc = xyes ; then
   using_custom_malloc=yes
fi
if test $using_custom_malloc = no ; then
   AC_CHECK_FUNCS(mallinfo malloc_good_size malloc_usable_size)
fi

if test "$enable_threads" = "yes"; then
  AC_CHECK_HEADERS(pthread.h)
  AC_CHECK_FUNCS(pthread_create)
fi

dnl ------------------------------------------------------
dnl Where do you live, libevent?  And how do we call you?

if test "$bwin32" = true; then
  TOR_LIB_WS32=-lws2_32
  # Some of the cargo-cults recommend -lwsock32 as well, but I don't
  # think it's actually necessary.
  TOR_LIB_GDI=-lgdi32
else
  TOR_LIB_WS32=
  TOR_LIB_GDI=
fi
AC_SUBST(TOR_LIB_WS32)
AC_SUBST(TOR_LIB_GDI)

dnl We need to do this before we try our disgusting hack below.
AC_CHECK_HEADERS([sys/types.h])

dnl This is a disgusting hack so we safely include older libevent headers.
AC_CHECK_TYPE(u_int64_t, unsigned long long)
AC_CHECK_TYPE(u_int32_t, unsigned long)
AC_CHECK_TYPE(u_int16_t, unsigned short)
AC_CHECK_TYPE(u_int8_t, unsigned char)

tor_libevent_pkg_redhat="libevent"
tor_libevent_pkg_debian="libevent-dev"
tor_libevent_devpkg_redhat="libevent-devel"
tor_libevent_devpkg_debian="libevent-dev"

TOR_SEARCH_LIBRARY(libevent, $trylibeventdir, [-levent $TOR_LIB_WS32], [
#ifdef WIN32
#include <winsock2.h>
#endif
#include <stdlib.h>
#include <sys/time.h>
#include <sys/types.h>
#include <event.h>], [
#ifdef WIN32
#include <winsock2.h>
#endif
void exit(int); void *event_init(void);],
    [
#ifdef WIN32
{WSADATA d; WSAStartup(0x101,&d); }
#endif
event_init(); exit(0);
], [--with-libevent-dir], [/opt/libevent])

dnl Now check for particular libevent functions.
save_LIBS="$LIBS"
save_LDFLAGS="$LDFLAGS"
save_CPPFLAGS="$CPPFLAGS"
LIBS="-levent $TOR_LIB_WS32 $LIBS"
LDFLAGS="$TOR_LDFLAGS_libevent $LIBS"
CPPFLAGS="$TOR_CPPFLAGS_libevent $CPPFLAGS"
AC_CHECK_FUNCS(event_get_version event_get_method event_set_log_callback)
LIBS="$save_LIBS"
LDFLAGS="$save_LDFLAGS"
CPPFLAGS="$save_CPPFLAGS"

dnl ------------------------------------------------------
dnl Where do you live, openssl?  And how do we call you?

tor_openssl_pkg_redhat="openssl"
tor_openssl_pkg_debian="libssl"
tor_openssl_devpkg_redhat="openssl-devel"
tor_openssl_devpkg_debian="libssl-dev"

TOR_SEARCH_LIBRARY(openssl, $tryssldir, [-lssl -lcrypto $TOR_LIB_GDI],
    [#include <openssl/rand.h>],
    [void RAND_add(const void *buf, int num, double entropy);],
    [RAND_add((void*)0,0,0); exit(0);], [--with-ssl-dir],
    [/usr/local/openssl /usr/lib/openssl /usr/local/ssl /usr/lib/ssl /usr/local /usr/athena /opt/openssl])

dnl XXXX check for OPENSSL_VERSION_NUMBER == SSLeay()

dnl ------------------------------------------------------
dnl Where do you live, zlib?  And how do we call you?

tor_openssl_pkg_redhat="zlib"
tor_openssl_pkg_debian="zlib1g"
tor_openssl_devpkg_redhat="zlib-devel"
tor_openssl_devpkg_debian="zlib1g-dev"

TOR_SEARCH_LIBRARY(zlib, $tryzlibdir, [-lz],
    [#include <zlib.h>],
    [const char * zlibVersion(void);],
    [zlibVersion(); exit(0);], [--with-zlib-dir],
    [/opt/zlib])

dnl Make sure to enable support for large off_t if available.

AC_SYS_LARGEFILE

AC_CHECK_HEADERS(unistd.h string.h signal.h ctype.h sys/stat.h sys/types.h fcntl.h sys/fcntl.h sys/time.h errno.h assert.h time.h, , AC_MSG_WARN(Some headers were not found, compilation may fail.  If compilation succeeds, please send your orconfig.h to the developers so we can fix this warning.))

AC_CHECK_HEADERS(netdb.h sys/ioctl.h sys/socket.h arpa/inet.h netinet/in.h pwd.h grp.h sys/un.h sys/uio.h)

dnl These headers are not essential

AC_CHECK_HEADERS(stdint.h sys/types.h inttypes.h sys/param.h sys/wait.h limits.h sys/limits.h netinet/in.h arpa/inet.h machine/limits.h syslog.h sys/time.h sys/resource.h inttypes.h utime.h sys/utime.h sys/mman.h netinet/in6.h malloc.h sys/syslimits.h malloc/malloc.h linux/types.h)

TOR_CHECK_PROTOTYPE(malloc_good_size, HAVE_MALLOC_GOOD_SIZE_PROTOTYPE,
[#ifdef HAVE_MALLOC_H
#include <malloc.h>
#endif
#ifdef HAVE_MALLOC_MALLOC_H
#include <malloc/malloc.h>
#endif])

AC_CHECK_HEADERS(net/if.h, net_if_found=1, net_if_found=0,
[#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif])
AC_CHECK_HEADERS(net/pfvar.h, net_pfvar_found=1, net_pfvar_found=0,
[#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#ifdef HAVE_NET_IF_H
#include <net/if.h>
#endif])
AC_CHECK_HEADERS(linux/netfilter_ipv4.h,
        linux_netfilter_ipv4=1, linux_netfilter_ipv4=0,
[#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#ifdef HAVE_LIMITS_H
#include <limits.h>
#endif
#ifdef HAVE_LINUX_TYPES_H
#include <linux/types.h>
#endif
#ifdef HAVE_NETINET_IN6_H
#include <netinet/in6.h>
#endif
#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif])

if test x$transparent = xtrue ; then
   transparent_ok=0
   if test x$net_if_found = x1 && test x$net_pfvar_found = x1 ; then
     transparent_ok=1
   fi
   if test x$linux_netfilter_ipv4 = x1 ; then
     transparent_ok=1
   fi
   if test x$transparent_ok = x1 ; then
     AC_DEFINE(USE_TRANSPARENT, 1, "Define to enable transparent proxy support")
     case $host in
       *-*-openbsd*)
         AC_DEFINE(OPENBSD, 1, "Define to handle pf on OpenBSD properly") ;;
     esac
   else
     AC_MSG_NOTICE([Transparent proxy support enabled, but missing headers.])
   fi
fi

AC_FUNC_FSEEKO

AC_CHECK_MEMBERS([struct timeval.tv_sec], , ,
[#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#ifdef HAVE_SYS_TIME_H
#include <sys/time.h>
#endif])

dnl In case we aren't given a working stdint.h, we'll need to grow our own.
dnl Watch out.

AC_CHECK_SIZEOF(int8_t)
AC_CHECK_SIZEOF(int16_t)
AC_CHECK_SIZEOF(int32_t)
AC_CHECK_SIZEOF(int64_t)
AC_CHECK_SIZEOF(uint8_t)
AC_CHECK_SIZEOF(uint16_t)
AC_CHECK_SIZEOF(uint32_t)
AC_CHECK_SIZEOF(uint64_t)
AC_CHECK_SIZEOF(intptr_t)
AC_CHECK_SIZEOF(uintptr_t)

dnl AC_CHECK_TYPES([int8_t, int16_t, int32_t, int64_t, uint8_t, uint16_t, uint32_t, uint64_t, intptr_t, uintptr_t])

AC_CHECK_SIZEOF(char)
AC_CHECK_SIZEOF(short)
AC_CHECK_SIZEOF(int)
AC_CHECK_SIZEOF(long)
AC_CHECK_SIZEOF(long long)
AC_CHECK_SIZEOF(__int64)
AC_CHECK_SIZEOF(void *)
AC_CHECK_SIZEOF(time_t)
AC_CHECK_SIZEOF(size_t)

AC_CHECK_TYPES([uint, u_char, ssize_t])

AC_CHECK_TYPES([struct in6_addr, struct sockaddr_in6, struct sockaddr_storage, sa_family_t], , ,
[#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#ifdef HAVE_NETINET_IN6_H
#include <netinet/in6.h>
#endif
#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#ifdef MS_WINDOWS
#define WIN32_WINNT 0x400
#define _WIN32_WINNT 0x400
#define WIN32_LEAN_AND_MEAN
#if defined(_MSC_VER) && (_MSC_VER < 1300)
#include <winsock.h>
#else
#include <winsock2.h>
#include <ws2tcpip.h>
#endif
#endif
])
AC_CHECK_MEMBERS([struct in6_addr.s6_addr32, struct in6_addr.s6_addr16], , ,
[#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#ifdef HAVE_NETINET_IN6_H
#include <netinet/in6.h>
#endif
#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#ifdef MS_WINDOWS
#define WIN32_WINNT 0x400
#define _WIN32_WINNT 0x400
#define WIN32_LEAN_AND_MEAN
#if defined(_MSC_VER) && (_MSC_VER < 1300)
#include <winsock.h>
#else
#include <winsock2.h>
#include <ws2tcpip.h>
#endif
#endif
])

AC_CHECK_TYPES([rlim_t], , ,
[#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#ifdef HAVE_SYS_TIME_H
#include <sys/time.h>
#endif
#ifdef HAVE_SYS_RESOURCE_H
#include <sys/resource.h>
#endif
])

AC_CACHE_CHECK([whether time_t is signed], tor_cv_time_t_signed, [
AC_RUN_IFELSE(AC_LANG_SOURCE([
#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#ifdef HAVE_SYS_TIME_H
#include <sys/time.h>
#endif
#ifdef HAVE_TIME_H
#include <time.h>
#endif
int main(int c, char**v) { if (((time_t)-1)<0) return 1; else return 0; }]),
  tor_cv_time_t_signed=no, tor_cv_time_t_signed=yes, tor_cv_time_t_signed=cross)
])

if test "$tor_cv_time_t_signed" = cross; then
  AC_MSG_NOTICE([Cross compiling: assuming that time_t is signed.])
fi

if test "$tor_cv_time_t_signed" != no; then
  AC_DEFINE([TIME_T_IS_SIGNED], 1,
            [Define to 1 iff time_t is signed])
fi

AC_CHECK_SIZEOF(socklen_t, , [AC_INCLUDES_DEFAULT()
#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
])

# We want to make sure that we _don't_ have a cell_t defined, like IRIX does.

AC_CHECK_SIZEOF(cell_t)

# Now make sure that NULL can be represented as zero bytes.
AC_CACHE_CHECK([whether memset(0) sets pointers to NULL], tor_cv_null_is_zero,
[AC_RUN_IFELSE([AC_LANG_SOURCE(
[[#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#ifdef HAVE_STDDEF_H
#include <stddef.h>
#endif
int main () { char *p1,*p2; p1=NULL; memset(&p2,0,sizeof(p2));
return memcmp(&p1,&p2,sizeof(char*))?1:0; }]])],
       [tor_cv_null_is_zero=yes],
       [tor_cv_null_is_zero=no],
       [tor_cv_null_is_zero=cross])])

if test "$tor_cv_null_is_zero" = cross ; then
  # Cross-compiling; let's hope that the target isn't raving mad.
  AC_MSG_NOTICE([Cross-compiling: we'll assume that NULL is represented as a sequence of 0-valued bytes.])
fi

if test "$tor_cv_null_is_zero" != no; then
  AC_DEFINE([NULL_REP_IS_ZERO_BYTES], 1,
            [Define to 1 iff memset(0) sets pointers to NULL])
fi

# And what happens when we malloc zero?
AC_CACHE_CHECK([whether we can malloc(0) safely.], tor_cv_malloc_zero_works,
[AC_RUN_IFELSE([AC_LANG_SOURCE(
[[#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#ifdef HAVE_STDDEF_H
#include <stddef.h>
#endif
int main () { return malloc(0)?0:1; }]])],
       [tor_cv_malloc_zero_works=yes],
       [tor_cv_malloc_zero_works=no],
       [tor_cv_malloc_zero_works=cross])])

if test "$tor_cv_malloc_zero_works" = cross; then
  # Cross-compiling; let's hope that the target isn't raving mad.
  AC_MSG_NOTICE([Cross-compiling: we'll assume that we need to check malloc() arguments for 0.])
fi

if test "$tor_cv_malloc_zero_works" = yes; then
  AC_DEFINE([MALLOC_ZERO_WORKS], 1,
            [Define to 1 iff malloc(0) returns a pointer])
fi

# whether we seem to be in a 2s-complement world.
AC_CACHE_CHECK([whether we are using 2s-complement arithmetic], tor_cv_twos_complement,
[AC_RUN_IFELSE([AC_LANG_SOURCE(
[[int main () { int problem = ((-99) != (~99)+1);
return problem ? 1 : 0; }]])],
       [tor_cv_twos_complement=yes],
       [tor_cv_twos_complement=no],
       [tor_cv_twos_complement=cross])])

if test "$tor_cv_twos_complement" = cross ; then
  # Cross-compiling; let's hope that the target isn't raving mad.
  AC_MSG_NOTICE([Cross-compiling: we'll assume that negative integers are represented with two's complement.])
fi

if test "$tor_cv_twos_complement" != no ; then
  AC_DEFINE([USING_TWOS_COMPLEMENT], 1,
            [Define to 1 iff we represent negative integers with two's complement])
fi

# Whether we should use the dmalloc memory allocation debugging library.
AC_MSG_CHECKING(whether to use dmalloc (debug memory allocation library))
AC_ARG_WITH(dmalloc,
[  --with-dmalloc          Use debug memory allocation library. ],
[if [[ "$withval" = "yes" ]]; then
  dmalloc=1
  AC_MSG_RESULT(yes)
else
  dmalloc=1
  AC_MSG_RESULT(no)
fi], [ dmalloc=0; AC_MSG_RESULT(no) ]
)

if [[ $dmalloc -eq 1 ]]; then
  AC_CHECK_HEADERS(dmalloc.h, , AC_MSG_ERROR(dmalloc header file not found. Do you have the development files for dmalloc installed?))
  AC_SEARCH_LIBS(dmalloc_malloc, [dmallocth dmalloc], , AC_MSG_ERROR(Libdmalloc library not found. If you enable it you better have it installed.))
  AC_DEFINE(USE_DMALLOC, 1, [Debug memory allocation library])
  AC_DEFINE(DMALLOC_FUNC_CHECK, 1, [Enable dmalloc's malloc function check])
  AC_CHECK_FUNCS(dmalloc_strdup dmalloc_strndup)
fi

AC_ARG_WITH(tcmalloc,
[  --with-tcmalloc         Use tcmalloc memory allocation library. ],
[ tcmalloc=yes ], [ tcmalloc=no ])

if test x$tcmalloc = xyes ; then
   LDFLAGS="-ltcmalloc $LDFLAGS"
fi

# Allow user to specify an alternate syslog facility
AC_ARG_WITH(syslog-facility,
[  --with-syslog-facility=LOG syslog facility to use (default=LOG_DAEMON)],
syslog_facility="$withval", syslog_facility="LOG_DAEMON")
AC_DEFINE_UNQUOTED(LOGFACILITY,$syslog_facility,[name of the syslog facility])
AC_SUBST(LOGFACILITY)

# Check for gethostbyname_r in all its glorious incompatible versions.
#   (This logic is based on that in Python's configure.in)
AH_TEMPLATE(HAVE_GETHOSTBYNAME_R,
  [Define this if you have any gethostbyname_r()])

AC_CHECK_FUNC(gethostbyname_r, [
  AC_MSG_CHECKING([how many arguments gethostbyname_r() wants])
  OLD_CFLAGS=$CFLAGS
  CFLAGS="$CFLAGS $MY_CPPFLAGS $MY_THREAD_CPPFLAGS $MY_CFLAGS"
  AC_COMPILE_IFELSE(AC_LANG_PROGRAM([
#include <netdb.h>
  ], [[
    char *cp1, *cp2;
    struct hostent *h1, *h2;
    int i1, i2;
    (void)gethostbyname_r(cp1,h1,cp2,i1,&h2,&i2);
  ]]),[
    AC_DEFINE(HAVE_GETHOSTBYNAME_R)
    AC_DEFINE(HAVE_GETHOSTBYNAME_R_6_ARG, 1,
     [Define this if gethostbyname_r takes 6 arguments])
    AC_MSG_RESULT(6)
  ], [
    AC_TRY_COMPILE([
#include <netdb.h>
    ], [
      char *cp1, *cp2;
      struct hostent *h1;
      int i1, i2;
      (void)gethostbyname_r(cp1,h1,cp2,i1,&i2);
    ], [
      AC_DEFINE(HAVE_GETHOSTBYNAME_R)
      AC_DEFINE(HAVE_GETHOSTBYNAME_R_5_ARG, 1,
        [Define this if gethostbyname_r takes 5 arguments])
      AC_MSG_RESULT(5)
   ], [
      AC_TRY_COMPILE([
#include <netdb.h>
     ], [
       char *cp1;
       struct hostent *h1;
       struct hostent_data hd;
       (void) gethostbyname_r(cp1,h1,&hd);
     ], [
       AC_DEFINE(HAVE_GETHOSTBYNAME_R)
       AC_DEFINE(HAVE_GETHOSTBYNAME_R_3_ARG, 1,
         [Define this if gethostbyname_r takes 3 arguments])
       AC_MSG_RESULT(3)
     ], [
       AC_MSG_RESULT(0)
     ])
  ])
 ])
 CFLAGS=$OLD_CFLAGS
])

AC_CACHE_CHECK([whether the C compiler supports __func__],
  tor_cv_have_func_macro,
  AC_COMPILE_IFELSE([
#include <stdio.h>
int main(int c, char **v) { puts(__func__); }],
  tor_cv_have_func_macro=yes,
  tor_cv_have_func_macro=no))

AC_CACHE_CHECK([whether the C compiler supports __FUNC__],
  tor_cv_have_FUNC_macro,
  AC_COMPILE_IFELSE([
#include <stdio.h>
int main(int c, char **v) { puts(__FUNC__); }],
  tor_cv_have_FUNC_macro=yes,
  tor_cv_have_FUNC_macro=no))

AC_CACHE_CHECK([whether the C compiler supports __FUNCTION__],
  tor_cv_have_FUNCTION_macro,
  AC_COMPILE_IFELSE([
#include <stdio.h>
int main(int c, char **v) { puts(__FUNCTION__); }],
  tor_cv_have_FUNCTION_macro=yes,
  tor_cv_have_FUNCTION_macro=no))

if test "$tor_cv_have_func_macro" = 'yes'; then
  AC_DEFINE(HAVE_MACRO__func__, 1, [Defined if the compiler supports __func__])
fi

if test "$tor_cv_have_FUNC_macro" = 'yes'; then
  AC_DEFINE(HAVE_MACRO__FUNC__, 1, [Defined if the compiler supports __FUNC__])
fi

if test "$tor_cv_have_FUNCTION_macro" = 'yes'; then
  AC_DEFINE(HAVE_MACRO__FUNCTION__, 1,
           [Defined if the compiler supports __FUNCTION__])
fi

# $prefix stores the value of the --prefix command line option, or
# NONE if the option wasn't set.  In the case that it wasn't set, make
# it be the default, so that we can use it to expand directories now.
if test "x$prefix" = "xNONE"; then
  prefix=$ac_default_prefix
fi

# and similarly for $exec_prefix
if test "x$exec_prefix" = "xNONE"; then
  exec_prefix=$prefix
fi

if test "x$CONFDIR" = "x"; then
  CONFDIR=`eval echo $sysconfdir/tor`
fi
AC_SUBST(CONFDIR)
AH_TEMPLATE([CONFDIR],[tor's configuration directory])
AC_DEFINE_UNQUOTED(CONFDIR,"$CONFDIR")

BINDIR=`eval echo $bindir`
AC_SUBST(BINDIR)
LOCALSTATEDIR=`eval echo $localstatedir`
AC_SUBST(LOCALSTATEDIR)

# Set CFLAGS _after_ all the above checks, since our warnings are stricter
# than autoconf's macros like.
if test "$ac_cv_c_compiler_gnu" = yes; then
  CFLAGS="$CFLAGS -Wall -g -O2"
else
  CFLAGS="$CFLAGS -g -O"
  enable_gcc_warnings=no
fi

# Add some more warnings which we use in development but not in the
# released versions.  (Some relevant gcc versions can't handle these.)
if test x$enable_gcc_warnings = xyes; then

  AC_COMPILE_IFELSE(AC_LANG_PROGRAM([], [
#if !defined(__GNUC__) || (__GNUC__ < 4)
#error
#endif]), have_gcc4=yes, have_gcc4=no)

  AC_COMPILE_IFELSE(AC_LANG_PROGRAM([], [
#if !defined(__GNUC__) || (__GNUC__ < 4) || (__GNUC__ == 4 && __GNUC_MINOR__ < 2)
#error
#endif]), have_gcc42=yes, have_gcc42=no)

  AC_COMPILE_IFELSE(AC_LANG_PROGRAM([], [
#if !defined(__GNUC__) || (__GNUC__ < 4) || (__GNUC__ == 4 && __GNUC_MINOR__ < 3)
#error
#endif]), have_gcc43=yes, have_gcc43=no)

  save_CFLAGS="$CFLAGS"
  CFLAGS="$CFLAGS -Wshorten-64-to-32"
  AC_COMPILE_IFELSE(AC_LANG_PROGRAM([], []), have_shorten64_flag=yes,
                    have_shorten64_flag=no)
  CFLAGS="$save_CFLAGS"

  CFLAGS="$CFLAGS -W -Wfloat-equal -Wundef -Wpointer-arith -Wstrict-prototypes -Wmissing-prototypes -Wwrite-strings -Wredundant-decls -Wchar-subscripts -Wcomment -Wformat=2 -Wwrite-strings -Wmissing-declarations -Wredundant-decls -Wnested-externs -Wbad-function-cast -Wswitch-enum -Werror"

  # Disabled, so we can use mallinfo(): -Waggregate-return

  if test x$have_gcc4 = xyes ; then 
    # These warnings break gcc 3.3.5 and work on gcc 4.0.2
    CFLAGS="$CFLAGS -Winit-self -Wmissing-field-initializers -Wdeclaration-after-statement -Wold-style-definition"
  fi

  if test x$have_gcc42 = xyes ; then 
    # These warnings break gcc 4.0.2 and work on gcc 4.2
    # XXXX020 Use -fstack-protector.
    # XXXX020 See if any of these work with earlier versions.
    CFLAGS="$CFLAGS -Waddress -Wmissing-noreturn -Wnormalized=id -Woverride-init -Wstrict-overflow=1"
    # We used to use -Wstrict-overflow=5, but that breaks us heavily under 4.3.
  fi

  if test x$have_gcc43 = xyes ; then 
    # These warnings break gcc 4.2 and work on gcc 4.3
    # XXXX020 See if any of these work with earlier versions.
    CFLAGS="$CFLAGS -Wextra -Warray-bounds"
  fi

  if test x$have_shorten64_flag = xyes ; then
    CFLAGS="$CFLAGS -Wshorten-64-to-32"
  fi

##This will break the world on some 64-bit architectures
# CFLAGS="$CFLAGS -Winline"
fi



CPPFLAGS="$CPPFLAGS $TOR_CPPFLAGS_libevent $TOR_CPPFLAGS_openssl $TOR_CPPFLAGS_zlib"

AC_CONFIG_FILES([Makefile tor.spec Doxyfile contrib/tor.sh contrib/torctl contrib/torify contrib/tor.logrotate contrib/Makefile contrib/osx/Makefile contrib/osx/TorBundleDesc.plist contrib/osx/TorBundleInfo.plist contrib/osx/TorDesc.plist contrib/osx/TorInfo.plist contrib/osx/TorStartupDesc.plist src/config/torrc.sample doc/tor.1 src/Makefile doc/Makefile doc/design-paper/Makefile doc/spec/Makefile src/config/Makefile src/common/Makefile src/or/Makefile src/win32/Makefile src/tools/Makefile contrib/suse/Makefile contrib/suse/tor.sh])
AC_OUTPUT

if test -x /usr/bin/perl && test -x ./contrib/updateVersions.pl ; then
  ./contrib/updateVersions.pl
fi