#
# Begin pthreads checking.
#
# First, decide whether to use multithreading or not.
#
# Enable multithreading by default on systems where it is known
# to work well, and where debugging of multithreaded programs
# is supported.
#

AC_MSG_CHECKING(whether to build with thread support)

case $host in
*-dec-osf*)
	use_threads=true ;;
[*-solaris2.[0-6]])
	# Thread signals are broken on Solaris 2.6; they are sometimes
	# delivered to the wrong thread.
	use_threads=false ;;
*-solaris*)
	use_threads=true ;;
*-ibm-aix*)
	use_threads=true ;;
*-hp-hpux10*)
	use_threads=false ;;
*-hp-hpux11*)
	use_threads=true ;;
*-sgi-irix*)
	use_threads=true ;;
*-sco-sysv*uw*|*-*-sysv*UnixWare*)
        # UnixWare
	use_threads=false ;;
*-*-sysv*OpenUNIX*)
        # UnixWare
	use_threads=true ;;
[*-netbsd[1234].*])
	# NetBSD earlier than NetBSD 5.0 has poor pthreads.
	#  Don't use it by default.
	use_threads=false ;;
*-netbsd*)
	use_threads=true ;;
*-openbsd*)
	# OpenBSD users have reported that named dumps core on
	# startup when built with threads.
	use_threads=false ;;
[*-freebsd[1234567].*])
	# Threads are broken at least up to FreeBSD 4.11.
	# FreeBSD 5, 6 and 7 we have never officially supported threads
	# on. YMMV
	use_threads=false ;;
*-freebsd*)
	use_threads=true ;;
[*-bsdi[234]*])
	# Thread signals do not work reliably on some versions of BSD/OS.
	use_threads=false ;;
*-bsdi5*)
	use_threads=true ;;
*-linux*)
   	# Threads are disabled on Linux by default because most
	# Linux kernels produce unusable core dumps from multithreaded
	# programs, and because of limitations in setuid().
	use_threads=false ;;	
*-darwin[[123456789]].*)
	use_threads=false ;;
*-darwin*.*)
	use_threads=true ;;
*)
	use_threads=false ;;
esac

AC_ARG_ENABLE(threads,
	[  --enable-threads	enable multithreading])
case "$enable_threads" in
	yes)
		use_threads=true
		;;
	no)
		use_threads=false
		;;
	'')
		# Use system-dependent default
		;;
	*)
	    	AC_MSG_ERROR([--enable-threads takes yes or no])
		;;
esac

if $use_threads
then
	AC_MSG_RESULT(yes)
else
	AC_MSG_RESULT(no)	
fi

if $use_threads
then
	#
	# Search for / configure pthreads in a system-dependent fashion.
	#
	case "$host" in
		*-freebsd*)
			# We don't want to set -lpthread as that break
			# the ability to choose threads library at final
			# link time and is not valid for all architectures.
			
			PTHREAD=
			if test "X$GCC" = "Xyes"; then
				saved_cc="$CC"
				CC="$CC -pthread"
				AC_MSG_CHECKING(for gcc -pthread support);
				AC_TRY_LINK([#include <pthread.h>],
					    [printf("%x\n", pthread_create);],
					    PTHREAD="yes"
					    AC_MSG_RESULT(yes),
					    AC_MSG_RESULT(no))
				CC="$saved_cc"
			fi
			if test "X$PTHREAD" != "Xyes"; then
				AC_CHECK_LIB(pthread, pthread_create,,
				AC_CHECK_LIB(thr, thread_create,,
				AC_CHECK_LIB(c_r, pthread_create,,
				AC_CHECK_LIB(c, pthread_create,,
				AC_MSG_ERROR("could not find thread libraries")))))
			fi
			;;
		*)
			AC_CHECK_LIB(pthread, pthread_create,,
				AC_CHECK_LIB(pthread, __pthread_create,,
				AC_CHECK_LIB(pthread, __pthread_create_system,,
				AC_CHECK_LIB(c_r, pthread_create,,
				AC_CHECK_LIB(c, pthread_create,,
				AC_MSG_ERROR("could not find thread libraries"))))))
		;;
	esac
fi
