Catch and dump unhandled exceptions in async task functions

The problem with relying on noexcept for this is that there is no stack.

1 files changed, 1 insertions, 1 deletions

diff --git a/build2/context b/build2/context
index bc73d5b..95030d8 100644
--- a/build2/context
+++ b/build2/context
@@ -138,7 +138,7 @@ namespace build2
   //   for (...)
   //   {
   //     sched.async (task_count,
-  //                  [] (...)
+  //                  [] (...) noexcept
   //                  {
   //                    phase_lock pl (run_phase::match);  // (2)
   //                    ...