- AC_MSG_RESULT([[cannot find ucontext. I'm going to try as if you had set --enable-context=pthreads !]])
- enable_context=pthreads
+ AC_ERROR([no appropriate backend found])
+ fi
+fi
+
+dnl #
+dnl # 3. allow decision to be overridden by user
+dnl #
+
+AC_MSG_CHECKING(what kind of backend should we use)
+AC_ARG_WITH(context,
+ [ --with-context=[ucontext/pthread] Use either (System V) swapcontext or pthread [[default=auto]].],,
+ with_context=auto)
+case $with_context in
+ ucontext) ;;
+ pthread) ;;
+ windows) ;;
+ auto) with_context=ucontext;;
+ *) AC_MSG_ERROR("--with-context must be either ucontext or pthread") ;;
+esac
+
+if test "x$with_context" = "xucontext" ; then
+ if test ".$mcsc" = .yes; then
+ AC_MSG_RESULT(found working ucontext. Great!)
+ AC_DEFINE([USE_UCONTEXT],1,[Define if we use ucontext or not])
+ else
+ if test ".$windows_context" = .yes ; then
+ AC_MSG_RESULT(use windows context portability layer.)
+ with_context=windows
+ else
+ AC_MSG_RESULT([[no working ucontext found. Try pthreads as a fallback]])
+ with_context=pthread