CONFIG: add runtime settings for mingw cross-compiled binaries

- WM_ARCH=win64 to indicate the runtime environment

ENH: cross-compile wmake toolchain for the target-side as well

etc/config.csh/settings

@@ -90,12 +90,22 @@ case Linux:
     endsw
     breaksw
 
-case Darwin:    # Presume x86_64, with clang (not gcc) as system compiler
+# Presume x86_64, with clang (not gcc) as system compiler
+case Darwin:
     setenv WM_ARCH darwin64
     if ("$WM_COMPILER" == Gcc) setenv WM_COMPILER Clang
     echo "Darwin support is clang/llvm only"
     breaksw
 
+# Presume x86_64, with mingw cross-compiled
+case MINGW*:
+case MSYS*:
+    WM_ARCH=win64
+    if ("$WM_COMPILER" == Gcc) setenv WM_COMPILER Mingw
+    setenv WM_COMPILER_LIB_ARCH 64  # Consistent with linux64Mingw
+    echo "Windows support (mingw64) is runtime only"
+    ;;
+
 case SunOS*:
     setenv WM_ARCH solaris64
     setenv WM_COMPILER_LIB_ARCH 64

etc/config.sh/settings

@@ -82,18 +82,27 @@ Linux)
     esac
     ;;
 
-Darwin)     # Presume x86_64, with clang (not gcc) as system compiler
+# Presume x86_64, with clang (not gcc) as system compiler
+Darwin)
     WM_ARCH=darwin64
     [ "$WM_COMPILER" = Gcc ] && WM_COMPILER=Clang
     echo "Darwin support is clang/llvm only" 1>&2
     ;;
 
+# Presume x86_64, with mingw cross-compiled
+MINGW* | MSYS*)
+    WM_ARCH=win64
+    [ "$WM_COMPILER" = Gcc ] && WM_COMPILER=Mingw
+    export WM_COMPILER_LIB_ARCH=64  # Consistent with linux64Mingw
+    echo "Windows support (mingw64) is runtime only" 1>&2
+    ;;
+
 SunOS*)
     WM_ARCH=solaris64
     export WM_COMPILER_LIB_ARCH=64
     ;;
 
-*)  # An unsupported operating system
+*)
     /bin/cat << UNSUPPORTED 1>&2
 ===============================================================================
 Operating system '$WM_ARCH' is unsupported by this OpenFOAM release.

wmake/src/Allmake

@@ -21,19 +21,26 @@ then
     exit 1
 fi
 
-case "$WM_COMPILER" in
-Mingw*)
-    # Host wmake toolchain with system gcc (when cross-compiling)
+
+if [ "${WM_COMPILER%Mingw}" != "$WM_COMPILER" ] && [ "$WM_ARCH" != win64 ]
+then
+    # Mingw cross-compilation
+
+    # Toolchain for build (system gcc)
     make \
         WM_COMPILER=Gcc WM_COMPILER_TYPE=system \
         WMAKE_BIN="${WM_PROJECT_DIR}/platforms/tools/${WM_ARCH}${WM_COMPILER}" \
         "$@"
-    ;;
 
-*)
+    # Toolchain for target (mingw)
+    make \
+        WMAKE_BIN="${WM_PROJECT_DIR}/platforms/tools/win64${WM_COMPILER}" \
+        "$@"
+else
+
     # Regular wmake toolchain
     make "$@"
-    ;;
-esac
+
+fi
 
 #------------------------------------------------------------------------------

wmake/src/Makefile

@@ -6,29 +6,20 @@
 #    \\/     M anipulation  |
 #------------------------------------------------------------------------------
 #     Copyright (C) 2011-2016 OpenFOAM Foundation
-#     Copyright (C) 2017-2019 OpenCFD Ltd.
+#     Copyright (C) 2017-2020 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/>.
+#     This file is part of OpenFOAM, distributed under GPL-3.0-or-later.
 #
 # File
 #     Makefile
 #
 # Description
-#     Makefile used to compile wmake utilities.
+#     Makefile for compiling wmake toolchain.
+#
+# Note
+#     The 'createCode' script is used to pre-generate the scanner code
+#     since ragel is not very prevalent.
 #
 #------------------------------------------------------------------------------
 
@@ -55,7 +46,7 @@ WM_COMPILE_OPTION = Opt
 GENERAL_RULES   = $(WM_DIR)/rules/General
 include $(GENERAL_RULES)/general
 
-archHost    := $(WM_ARCH)$(WM_COMPILER)
+archBuild   := $(WM_ARCH)$(WM_COMPILER)
 archTarget  := $(shell basename $(WMAKE_BIN))
 
 
@@ -71,8 +62,8 @@ all: $(WMAKE_BIN)/lemon$(EXT_EXE) $(WMAKE_BIN)/wmkdepend$(EXT_EXE) message
 old: $(WMAKE_BIN)/wmkdep$(EXT_EXE)
 
 message:
-ifneq ($(archHost),$(archTarget))
-	@echo "built wmake-bin ($(archTarget)) for $(archHost) host"
+ifneq ($(archBuild),$(archTarget))
+	@echo "built wmake-bin ($(archTarget)) with $(archBuild)"
 else
 	@echo "built wmake-bin ($(archTarget))"
 endif