+AC_HEADER_TIME
+AC_CHECK_HEADERS([sys/socket.h winsock.h winsock2.h \
+ sys/stat.h \
+ ucontext.h \
+ pthread.h \
+ windows.h \
+ sys/time.h \
+ errno.h unistd.h ])
+AC_CHECK_FUNCS([gettimeofday usleep \
+ getdtablesize \
+ sysconf])
+
+AC_ARG_ENABLE(context,
+ [ --enable-context=[ucontext/pthread] Use either (System V) swapcontext or pthread [[default=ucontext]].],,
+ enable_context=ucontext)
+AC_MSG_CHECKING(on top of what can we build the contexts)
+if test "x$enable_context" = "xucontext"; then
+ ac_header=ucontext.h
+ as_ac_Header=`echo "ac_cv_header_$ac_header" | $as_tr_sh`
+ if test `eval echo '${'$as_ac_Header'}'` = yes; then
+ AC_MSG_RESULT(found ucontext.h. Great!)
+ else
+ ac_header=windows.h
+ as_ac_Header=`echo "ac_cv_header_$ac_header" | $as_tr_sh`
+ if test `eval echo '${'$as_ac_Header'}'` = yes; then
+ AC_MSG_RESULT(you don't have ucontext.h but we provide an alternative for windows so you should be fine.")
+ else
+ AC_MSG_RESULT([[cannot find ucontext. I'm going to try as if you had set --enable-context=pthreads !]])
+ enable_context=pthreads
+ fi
+ fi
+else if test "x$enable_context" = "xpthread"; then
+ AC_CHECK_LIB(pthread,pthread_create,,
+ [AC_MSG_ERROR([[Cannot find pthreads, no way (try --enable-context=ucontext if you haven't already tried).]])])
+ AC_DEFINE([USE_PTHREADS],1,[Define if we USE pthreads or not])
+ AC_MSG_RESULT(You have pthreads. Let's use them.)
+else
+ AC_MSG_ERROR("--enable-context must be either ucontext or pthread")
+fi fi
+