the target is named by mcpp, and a sixth patch site was found by enumerating

README.md

@@ -6,11 +6,11 @@ C library.
 
 ```toml
 [dependencies]
-openkal-llvm-runtime = "0.13.0"
+openkal-llvm-runtime = "0.14.0"
 ```
 
 > **Engine floor (mcpp 2026.9.20.1):** this version of this package pins
-> `openkal-musl 0.18.0` and inherits its `[c-abi]` declaration. The engine
+> `openkal-musl 0.19.0` and inherits its `[c-abi]` declaration. The engine
 > assembles the verification probe's command line in one place that REFUSES
 > to run it without a target selection (`cenv_probe::assemble_argv`), and
 > `cenv::realise` forces `-fno-short-wchar` on freestanding wchar. Older

llvm/PATCHES.md

@@ -155,6 +155,32 @@ openkal-musl 的 `[c-abi] presents = "posix"` 把它和 `_WIN32`、`__MINGW32__`
 
 ---
 
+## 第六处:`compiler-rt/lib/builtins/int_lib.h`(2026-09-21)
+
+前五处是按「撤掉 `_WIN32` 后会落错分支」找出来的。**第六处是按「撤掉 `__CYGWIN__` 后会
+落错分支」找出来的,而当时没有人去找第二遍。**
+
+```c
+#if defined(__ELF__) || defined(__MINGW32__) || ... || defined(__CYGWIN__)
+    /* __attribute__((alias)) —— PE 要走的就是这一支 */
+#elif defined(__APPLE__) ...
+#elif defined(_WIN32) || defined(__UEFI__) ...
+#else
+#error Unsupported target
+```
+
+这个文件今天**靠 `__CYGWIN__` 偶然工作**:`_WIN32`/`__MINGW32__` 被 `[c-abi] presents =
+"posix"` 压掉,`__ELF__` 为假,只剩它。mcpp 撤掉 `__CYGWIN__` 之后(2026.9.21.1 的下一版),
+三支全部落空,直接 `#error`。
+
+它**不是**已安装的头,只由本包自己的构建编译,所以按本文件的规矩用私有 define
+`OPENKAL_TARGET_WINDOWS`——而 `__libunwind_config.h` 反过来用 `__MCPP_TARGET_WINDOWS__`,
+因为它**是**已安装的。两者读不同的宏,回答同一个关于同一个目标的问题,这正是下面那一节
+要求的性质。
+
+⚠️ **下一次改这棵树,`grep` 的清单要加上 `__CYGWIN__`**:
+`grep -rn "_WIN32\|_WIN64\|__MINGW32__\|__MINGW64__\|__CYGWIN__"`。
+
 ## ⭐ 一个名字,不是五个
 
 五处补丁全部守卫在 **`OPENKAL`** 上,`cflags` 和 `cxxflags` 各给一次

llvm/compiler-rt/lib/builtins/int_lib.h

@@ -48,8 +48,29 @@
 #define XSTR(a) STR(a)
 #define SYMBOL_NAME(name) XSTR(__USER_LABEL_PREFIX__) #name
 
+// ─── openkal ─── BEGIN
+// `OPENKAL_TARGET_WINDOWS` joins this guard, and the alternative was a hard
+// `#error Unsupported target` a release from now.
+//
+// This target is PE, and PE takes the first branch: `__attribute__((alias))`
+// is what the GNU/clang toolchain emits for it. Today that branch is reached
+// through `__CYGWIN__`, which mcpp defines only because nothing else named
+// the target --- BY ACCIDENT, not by this file's intent. `_WIN32` and
+// `__MINGW32__` are suppressed here on purpose (`[c-abi] presents = "posix"`)
+// and `__ELF__` is false, so when `__CYGWIN__` is withdrawn --- it is, one
+// release after mcpp 2026.9.21.1 --- every operand of this `#if` goes false,
+// `__APPLE__` and `_WIN32`/`__UEFI__` below are false too, and the `#else`
+// is `#error Unsupported target`.
+//
+// The private define is the right name here, not `__mcpp_target_windows__`:
+// this file is NOT installed, it is compiled only by this package's own
+// build, and `mcpp.toml` carries `OPENKAL_TARGET_WINDOWS` to it in `cflags`.
+// That is the same rule the other five patches in this tree follow, and the
+// reason `__libunwind_config.h` does the opposite --- it IS installed. See
+// `llvm/PATCHES.md`.
 #if defined(__ELF__) || defined(__MINGW32__) || defined(__wasm__) ||           \
-    defined(_AIX) || defined(__CYGWIN__)
+    defined(_AIX) || defined(__CYGWIN__) || defined(OPENKAL_TARGET_WINDOWS)
+// ─── openkal ─── END
 #define COMPILER_RT_ALIAS(name, aliasname) \
   COMPILER_RT_ABI __typeof(name) aliasname __attribute__((__alias__(#name)));
 #elif defined(__APPLE__)

llvm/libunwind/include/__libunwind_config.h

@@ -54,15 +54,33 @@
 // through `unwind.h` and `libunwind.h`, both public), so it cannot read
 // `OPENKAL_TARGET_WINDOWS` --- that is this package's own private build
 // define (mcpp.toml) and an application calling `unw_getcontext` directly
-// against `unw_context_t` does not see it. `__CYGWIN__` is read instead,
-// for the same reason `openkal-musl`'s `bits/setjmp.h` reads it: mcpp keeps
-// it defined target-wide, an application's compile included.
+// against `unw_context_t` does not see it. `__MCPP_TARGET_WINDOWS__` is read
+// instead: mcpp states the target under its OWN name, target-wide, an
+// application's compile included.
+//
+// TWO OPERANDS COVER EVERY ENGINE AND REMOVE THE ORDERING CONSTRAINT. One up
+// to and including 2026.9.21.1 defines `__CYGWIN__`, which answers; the
+// release that withdraws it defines `__MCPP_TARGET_WINDOWS__`, which answers
+// instead. No engine defines neither, so this header has no flag day and the
+// two releases may land in either order. The second operand goes once the
+// withdrawal has shipped.
+//
+// 2026.9.21.1 spelt the name in lower case and it is not read here: that
+// spelling existed for one release, nothing consumed it, and the release that
+// withdraws `__CYGWIN__` renames it in the same change. Project-owned macros
+// are upper case; lower case belongs to the compiler's own predefines, which
+// mcpp supplies but does not own.
+//
+// THE OLD NAME WAS BORROWED AND MEANT SOMETHING ELSE. Upstream reads
+// `__CYGWIN__` as "Win32 is available"; a 30-member measurement found four
+// packages doing exactly that and reaching `#include <windows.h>`. It
+// answered this file's question only by accident.
 // `UnwindRegistersSave.S` writes exactly the record sized here and reads
 // `OPENKAL_TARGET_WINDOWS` rather than `__CYGWIN__`, because it is NOT
 // installed --- compiled only by this package's own build, like
 // `okm_setjmp.S`. The two answer the same question about the same target
 // without reading the same macro, which is what has to hold; see that file.
-#  if defined(_WIN64) || defined(__CYGWIN__)
+#  if defined(_WIN64) || defined(__MCPP_TARGET_WINDOWS__) || defined(__CYGWIN__)
 // ─── openkal ─── END
 #    define _LIBUNWIND_CONTEXT_SIZE 54
 #    ifdef __SEH__

mcpp.toml

@@ -1,7 +1,7 @@
 [package]
 namespace   = "mcpplibs"
 name        = "openkal-llvm-runtime"
-version     = "0.13.0"
+version     = "0.14.0"
 description = "LLVM's C++ runtime libraries — libc++, libc++abi and libunwind — configured for openkal-musl rather than for a host C library."
 license     = "Apache-2.0"
 authors     = ["mcpplibs"]
@@ -216,7 +216,7 @@ sources = [
 cflags = ["-DDISABLE_AARCH64_FMV=1"]
 
 [dependencies]
-openkal-musl = "0.18.0"
+openkal-musl = "0.19.0"
 
 [build]