ENH: handle wmake -debug option via FOAM_EXTRA_CXX_FLAGS

- ensures that subsequent Allwmake scripts know about it.

ENH: add bin/tools/query-detect wrapper for wmake have_* scripts

CONFIG: use project/ThirdParty without additional sanity checks

- no need to test for Allwmake or platforms/ if ThirdParty is located
  within the project directory itself.

COMP: add simple mpi test to 00-dummy

- for testing library linkage, etc.

applications/test/00-dummy/library/mpi/Make/files

@@ -0,0 +1,4 @@
+/* Install into central FOAM_MPI_LIBBIN for 'fake' builds (test packaging) */
+dummyMpiLib.C
+
+LIB = $(FOAM_MPI_LIBBIN)/libTestDummyMpi

applications/test/00-dummy/library/mpi/Make/options

@@ -0,0 +1,17 @@
+/* Disable normal project defaults */
+PROJECT_INC =
+PROJECT_LIBS =
+
+sinclude $(GENERAL_RULES)/mplib$(WM_MPLIB)
+sinclude $(DEFAULT_RULES)/mplib$(WM_MPLIB)
+
+/* Default is PROJECT LIB/mpi target */
+ifeq (,$(FOAM_MPI_LIBBIN))
+    FOAM_MPI_LIBBIN := $(FOAM_LIBBIN)/$(FOAM_MPI)
+endif
+
+EXE_INC = \
+    -I.. \
+    $(PFLAGS) $(PINC) $(c++LESSWARN) -DFOAM_MPI=\"$(FOAM_MPI)\"
+
+LIB_LIBS = $(PLIBS)

applications/test/00-dummy/library/mpi/dummyMpiLib.C

@@ -0,0 +1,76 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | www.openfoam.com
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+    Copyright (C) 2020 OpenCFD Ltd.
+-------------------------------------------------------------------------------
+License
+    This file is part of OpenFOAM.
+
+    OpenFOAM is free software: you can redistribute it and/or modify it
+    under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
+    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+    for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
+
+\*---------------------------------------------------------------------------*/
+
+#include "dummyLib.H"
+#include <iostream>
+#include <mpi.h>
+
+// * * * * * * * * * * * * * * Global Functions  * * * * * * * * * * * * * * //
+
+bool Foam::Detail::dummyLib::hasMPI()
+{
+    return true;
+}
+
+
+bool Foam::Detail::dummyLib::printMPI()
+{
+    int rank = 0, nprocs = 0;
+
+    MPI_Init(nullptr, nullptr);
+
+    MPI_Comm_size(MPI_COMM_WORLD, &nprocs);
+    MPI_Comm_rank(MPI_COMM_WORLD, &rank);
+
+    // Hello world
+    std::cout
+        <<
+        (
+            std::string("mpi rank ")
+          + std::to_string(rank) + '/' + std::to_string(nprocs)
+          + '\n'
+        );
+
+    MPI_Finalize();
+
+    #ifdef FOAM_MPI
+    if (rank == 0)
+    {
+        std::cout
+            <<
+            (
+                std::string("FOAM_MPI=") + std::string(FOAM_MPI)
+              + '\n'
+            );
+    }
+    #endif
+
+    return rank == 0;
+}
+
+
+// ************************************************************************* //