start with openwatcom v2

cmake/modules/FindOpenWatcom.cmake

@@ -0,0 +1,86 @@
+# FindOpenWatcom.cmake
+#
+# Locate an Open Watcom v2 toolchain usable for building the 16-bit DOS
+# mars-nwe DOS utilities on a Linux host.
+#
+# Result variables:
+#   OpenWatcom_FOUND
+#   OPENWATCOM_WCL
+#   OPENWATCOM_WCC
+#   OPENWATCOM_WASM
+#   OPENWATCOM_WLINK
+#   OPENWATCOM_BIN_DIR
+#   OPENWATCOM_ROOT
+#   OPENWATCOM_ENV
+#
+# This module intentionally does not enable a CMake language/toolchain. The
+# DOS utilities are built via custom commands. OPENWATCOM_ENV is provided so
+# wcl can find its helper programs such as wcc, wlink and include files.
+
+set(_OPENWATCOM_HINTS)
+
+if(DEFINED ENV{WATCOM})
+    list(APPEND _OPENWATCOM_HINTS "$ENV{WATCOM}")
+endif()
+
+list(APPEND _OPENWATCOM_HINTS
+    /opt/watcom
+    /usr/local/watcom
+    /usr/local/open-watcom-v2
+    /opt/open-watcom-v2
+)
+
+find_program(OPENWATCOM_WCL
+    NAMES wcl owcc
+    HINTS ${_OPENWATCOM_HINTS}
+    PATH_SUFFIXES binl binnt binw bin
+)
+
+find_program(OPENWATCOM_WCC
+    NAMES wcc
+    HINTS ${_OPENWATCOM_HINTS}
+    PATH_SUFFIXES binl binnt binw bin
+)
+
+find_program(OPENWATCOM_WASM
+    NAMES wasm
+    HINTS ${_OPENWATCOM_HINTS}
+    PATH_SUFFIXES binl binnt binw bin
+)
+
+find_program(OPENWATCOM_WLINK
+    NAMES wlink
+    HINTS ${_OPENWATCOM_HINTS}
+    PATH_SUFFIXES binl binnt binw bin
+)
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(OpenWatcom
+    REQUIRED_VARS
+        OPENWATCOM_WCL
+        OPENWATCOM_WCC
+        OPENWATCOM_WASM
+        OPENWATCOM_WLINK
+)
+
+if(OpenWatcom_FOUND)
+    get_filename_component(OPENWATCOM_BIN_DIR "${OPENWATCOM_WCL}" DIRECTORY)
+    get_filename_component(OPENWATCOM_ROOT "${OPENWATCOM_BIN_DIR}" DIRECTORY)
+
+    # wcl starts helper tools such as wcc/wlink by name. Therefore finding the
+    # absolute wcl path is not enough; the Watcom bin directory must be in PATH
+    # at build time. WATCOM and INCLUDE are also expected by many installations.
+    set(OPENWATCOM_ENV
+        "WATCOM=${OPENWATCOM_ROOT}"
+        "INCLUDE=${OPENWATCOM_ROOT}/h:${OPENWATCOM_ROOT}/h/nt:${OPENWATCOM_ROOT}/h/os2"
+        "EDPATH=${OPENWATCOM_ROOT}/eddat"
+        "PATH=${OPENWATCOM_BIN_DIR}:$ENV{PATH}"
+    )
+endif()
+
+mark_as_advanced(
+    OPENWATCOM_WCL
+    OPENWATCOM_WCC
+    OPENWATCOM_WASM
+    OPENWATCOM_WLINK
+)