MPI.jl 0.20 compat (#35)

* MPI.jl 0.20 compat

* switch to MPI.ANY_SOUCE

Author: simonbyrne

Project.toml

@@ -10,7 +10,7 @@ Serialization = "9e88b42a-f829-5b0c-bbe9-9e923198166b"
 Sockets = "6462fe0b-24de-5631-8697-dd941f90decc"
 
 [compat]
-MPI = "0.14, 0.15, 0.19"
+MPI = "0.14, 0.15, 0.19, 0.20"
 julia = "1.6"
 
 [extras]

src/mpimanager.jl

@@ -397,7 +397,7 @@ end
 function receive_event_loop(mgr::MPIManager)
     num_send_loops = 0
     while !isready(mgr.initiate_shutdown)
-        (hasdata, stat) = MPI.Iprobe(MPI.MPI_ANY_SOURCE, 0, mgr.comm)
+        (hasdata, stat) = MPI.Iprobe(isdefined(MPI, :ANY_SOURCE) ? MPI.ANY_SOURCE : MPI.MPI_ANY_SOURCE, 0, mgr.comm)
         if hasdata
             count = MPI.Get_count(stat, UInt8)
             buf = Array{UInt8}(undef, count)