port: add MSVC600 CPython compatibility layer

README.md

@@ -11,17 +11,18 @@ The CPython baseline is kept in `cpython/` at tag `v3.11.16`. The MSVC600
 bundle is kept in `MSVC600/` as a local external prerequisite and is not part of
 the distributable project source.
 
-The first VC6 compiler probe succeeds under Wine. A direct compile of
-`cpython/Programs/python.c` currently fails in CPython headers because VC6
-lacks or does not understand several facilities used by CPython 3.11:
+The public-header probe and a real `Py_BUILD_CORE` translation unit now compile
+under MSVC600 through the project compatibility layer:
 
-- C99 `inttypes.h` and related integer-format definitions
-- C99 `inline` syntax in C mode
-- newer `__declspec(deprecated)` annotations
-- modern pointer-width/type configuration expected by `pyport.h`
-- the CPython 3.11 Visual Studio/MSBuild project model
+- `cpython/Programs/python.c` compiles successfully.
+- `cpython/Modules/main.c` compiles successfully.
+- `cpython/Python/pylifecycle.c` is the current larger-core probe and remains
+  blocked by CPython 3.11 C99 initializers, mixed declarations, and additional
+  legacy-compiler/platform differences.
 
-These are expected porting blockers and are recorded in `PORT_STATUS.md`.
+This is still an experimental porting workspace, not a completed Windows 98
+build. Exact verified milestones and blockers are recorded in
+`PORT_STATUS.md`.
 
 ## Toolchain policy