port: advance MSVC600 CPython compatibility frontier

compat/msvc600/pathcch.h

@@ -0,0 +1,84 @@
+#ifndef PYWIN9X_COMPAT_MSVC600_PATHCCH_H
+#define PYWIN9X_COMPAT_MSVC600_PATHCCH_H
+
+/*
+ * Narrow PathCchFindExtension compatibility for the VC6/MSVC600 probe.
+ *
+ * CPython 3.11's Modules/getpath.c includes <pathcch.h> only to call
+ * PathCchFindExtension() from getpath_isxfile().  MSVC 6.0's Windows SDK
+ * predates PathCch, so provide just that one API shape for the project-local
+ * VC6 include path.  Modern builds should keep using the platform SDK header;
+ * this file is not installed into CPython or a system include directory.
+ */
+
+#if defined(_MSC_VER) && _MSC_VER <= 1200
+
+#ifndef _WINDOWS_
+#include <windows.h>
+#endif
+#include <stddef.h>
+
+#ifndef PCWSTR
+typedef const WCHAR *PCWSTR;
+#endif
+#ifndef PWSTR
+typedef WCHAR *PWSTR;
+#endif
+#ifndef S_OK
+#define S_OK ((HRESULT)0L)
+#endif
+#ifndef E_INVALIDARG
+#define E_INVALIDARG ((HRESULT)0x80070057L)
+#endif
+
+static HRESULT
+PathCchFindExtension(PCWSTR pszPath, size_t cchPath, PCWSTR *ppszExt)
+{
+    size_t i;
+    size_t last_sep;
+    size_t last_dot;
+    int have_dot;
+
+    if (pszPath == NULL || ppszExt == NULL || cchPath == 0) {
+        return E_INVALIDARG;
+    }
+
+    last_sep = 0;
+    last_dot = 0;
+    have_dot = 0;
+
+    for (i = 0; i < cchPath; ++i) {
+        WCHAR ch = pszPath[i];
+        if (ch == L'\0') {
+            if (have_dot) {
+                *ppszExt = pszPath + last_dot;
+            }
+            else {
+                *ppszExt = pszPath + i;
+            }
+            return S_OK;
+        }
+        if (ch == L'\\' || ch == L'/' || ch == L':') {
+            last_sep = i + 1;
+            have_dot = 0;
+        }
+        else if (ch == L'.' && i >= last_sep) {
+            last_dot = i;
+            have_dot = 1;
+        }
+    }
+
+    *ppszExt = NULL;
+    return E_INVALIDARG;
+}
+
+#else
+/*
+ * This compatibility header is intentionally scoped to VC6.  If a modern
+ * compiler finds it, the include path is wrong: use the real Windows SDK
+ * pathcch.h instead to avoid shadowing the platform declaration.
+ */
+#error "compat/msvc600/pathcch.h is only for MSVC 6.0; use the Windows SDK pathcch.h on modern compilers"
+#endif
+
+#endif /* PYWIN9X_COMPAT_MSVC600_PATHCCH_H */

compat/msvc600/stdint.h

@@ -0,0 +1,45 @@
+#ifndef PYTHON_WIN9X_MSVC600_STDINT_H
+#define PYTHON_WIN9X_MSVC600_STDINT_H
+
+/* VC6-only fallback for the C99 <stdint.h> header.
+ *
+ * Visual C++ 6.0 (_MSC_VER 1200) predates C99 and ships no <stdint.h>. This
+ * project-local header is found ahead of any system <stdint.h> only because
+ * compat/msvc600 is placed first on the VC6 probe scripts' include path
+ * (scripts/vc6-probe.sh, scripts/vc6-probe-core.sh, scripts/vc6-probe-
+ * pythoncore-frontier.sh); it is never installed anywhere a standards-
+ * conforming compiler's own <stdint.h> would be found instead, so it never
+ * shadows a real one.
+ *
+ * First consumer: cpython/Modules/_blake2/impl/blake2.h and
+ * blake2-impl.h, which use only uint8_t, uint32_t, and uint64_t (verified
+ * by grepping every fixed-width identifier used across Modules/_blake2/,
+ * including the blake2b/blake2s/*-ref.c reference implementations and
+ * clinic-generated wrappers: no int8_t/int16_t/int32_t/int64_t or intptr_t/
+ * uintptr_t appear anywhere in that tree). `size_t` is used too, but that
+ * already comes from <stddef.h>, which VC6 has natively.
+ *
+ * compat/msvc600/inttypes.h already defines exactly these typedefs (plus
+ * the PRI* macros CPython's own Include/pyport.h needs from a real C99
+ * <inttypes.h>) for this same VC6 target. Rather than re-declaring
+ * uint8_t/uint32_t/uint64_t a second time under a second include guard
+ * (which would risk a duplicate-typedef error in any translation unit that
+ * ends up including both this header and <inttypes.h>, e.g. anything that
+ * pulls in both Python.h and a <stdint.h>-using third-party header like
+ * blake2.h), this header just forwards to it. inttypes.h's own include
+ * guard makes this forwarding idempotent no matter which of the two headers
+ * a given translation unit reaches first.
+ *
+ * Width assumptions (all already relied upon by inttypes.h and unchanged
+ * here): uint8_t = unsigned char (1 byte), uint32_t = unsigned long
+ * (4 bytes on Win32/ILP32), uint64_t = unsigned __int64 (VC6's non-standard
+ * 64-bit extension, 8 bytes). These match the sizes BLAKE2 requires.
+ */
+
+#if !defined(_MSC_VER) || _MSC_VER >= 1300
+#error "compat/msvc600/stdint.h is a VC6-only (_MSC_VER < 1300) fallback; a standard <stdint.h> should be used instead."
+#endif
+
+#include "inttypes.h"
+
+#endif /* PYTHON_WIN9X_MSVC600_STDINT_H */