docs/07: the two new rows state the fallback without addressing the reader

The style check refuses the second person in a reference document. Both
rows said what a rule reads an absent variable as by addressing it
directly; they now state it.

Author: speak-agent

docs/07-build-mcpp.md

@@ -659,7 +659,7 @@ The running program receives the build context as `MCPP_*` variables
 | `MCPP_CXX_STDLIB` *(2026.9.6.3+)* | `mcpp::cxx_stdlib()` | the C++ standard library the resolved toolchain uses — `libstdc++`, `libc++`, `msvc-stl`; empty when no toolchain resolved. A different question from `MCPP_TARGET_LIBC`, which is the C library |
 | `MCPP_ACCEL` *(2026.9.5.2+)* | `mcpp::accel()` | the device axis of this build, resolved — `--accel` / `--no-accel` over `[build] accel` — in the wire form `cuda12.9+{sm_89} ptx>=89`; empty when the build asks for no accelerator. A rule package derives its own flags (`-gencode`, `--offload-arch`) from it, so the architecture set is written once, in the manifest. The same value feeds the `cfg(accelerator = "…")` layer key |
 | `MCPP_LANGUAGE_MODULES` *(2026.9.7.1+)* | -- | `1` when the declaring package sets `[language] modules`, `0` otherwise. A rule that GENERATES a consumer-facing declaration reads it to choose between a module interface and a header, so a project states that once and never again. An older engine leaves it absent, which a rule reads as `0` -- the behaviour every consumer had before the variable existed |
-| `MCPP_PKG_NAME` *(2026.9.7.1+)* | -- | The `[package] name` of the package this program builds. Every name a rule generates is derived from it: the module a consumer imports, the namespace the accessors sit in, the symbols in a generated header. Before it existed the closest available answer was the leaf of `MCPP_MANIFEST_DIR`, which is a directory name -- so a package named `vulkan-saxpy` in a directory named `app` generated `app.shaders`, and every `<something>/app/` in a workspace claimed the same module. Absent under an older engine, which a rule reads as "use whatever you used before" |
+| `MCPP_PKG_NAME` *(2026.9.7.1+)* | -- | The `[package] name` of the package this program builds. Every name a rule generates is derived from it: the module a consumer imports, the namespace the accessors sit in, the symbols in a generated header. Before it existed the closest available answer was the leaf of `MCPP_MANIFEST_DIR`, which is a directory name -- so a package named `vulkan-saxpy` in a directory named `app` generated `app.shaders`, and every `<something>/app/` in a workspace claimed the same module. Absent under an older engine, which a rule reads as a signal to keep its previous derivation |
 | `MCPP_PKG_NAMESPACE` *(2026.9.7.1+)* | -- | The `[package] namespace`. Empty when the package declares none. A rule that must produce a name unique across an index uses the pair rather than the name alone, because package identity is `(namespace, name)` |
 | `MCPP_DEVICE_SOURCES` *(2026.9.5.2+)* | `mcpp::device_sources()` | the device-kind sources (`.cu`, `.hip`, …) the package's effective `sources` match, package-root-relative, one per line; empty when there are none. The engine compiles none of them — the rule package this program imports turns each into an `mcpp::action`. Already narrowed: a `{ glob, accel }` entry the build does not cover contributes nothing, so `--no-accel` yields an empty list |
 | `MCPP_OUT_DIR` | `mcpp::out_dir()` | a writable scratch/output dir owned by mcpp |

docs/zh/07-build-mcpp.md

@@ -563,7 +563,7 @@ mcpp 会把它自己构建时用的**同一份** std 模块暂存过来,缓存
 | `MCPP_CXX_STDLIB` *(2026.9.6.3+)* | `mcpp::cxx_stdlib()` | 解析出的工具链使用的 C++ 标准库 —— `libstdc++`、`libc++`、`msvc-stl`;没有工具链解析时为空串。与 `MCPP_TARGET_LIBC` 不是同一个问题,后者是 C 库 |
 | `MCPP_ACCEL` *(2026.9.5.2+)* | `mcpp::accel()` | 本次构建的设备轴,已解析 —— `--accel` / `--no-accel` 优先于 `[build] accel` —— 线上形态 `cuda12.9+{sm_89} ptx>=89`;不要加速器时为空串。规则包从它推导自己的开关(`-gencode`、`--offload-arch`),架构集合因此只在 manifest 写一次。同一个值也喂给 `cfg(accelerator = "…")` 这个 layer 键 |
 | `MCPP_LANGUAGE_MODULES` *(2026.9.7.1+)* | -- | 声明它的那个包设了 `[language] modules` 时为 `1`,否则 `0`。**生成**面向消费者声明的规则读它来在模块接口与头文件之间选择,项目因此只需说一次。旧引擎不设这个变量,规则把缺席读作 `0` —— 也就是这个变量存在之前每个消费者的行为 |
-| `MCPP_PKG_NAME` *(2026.9.7.1+)* | -- | 这个程序所构建的包的 `[package] name`。规则生成的每个名字都由它推导:消费者导入的模块、访问器所在的命名空间、生成头里的符号。在它存在之前,可用的最接近的答案是 `MCPP_MANIFEST_DIR` 的末段,那是目录名 —— 于是一个叫 `vulkan-saxpy` 的包放在名为 `app` 的目录下会生成 `app.shaders`,而工作区里每一个 `<something>/app/` 都声称拥有同一个模块。旧引擎下缺席,规则把缺席读作「沿用你之前用的那个」 |
+| `MCPP_PKG_NAME` *(2026.9.7.1+)* | -- | 这个程序所构建的包的 `[package] name`。规则生成的每个名字都由它推导:消费者导入的模块、访问器所在的命名空间、生成头里的符号。在它存在之前,可用的最接近的答案是 `MCPP_MANIFEST_DIR` 的末段,那是目录名 —— 于是一个叫 `vulkan-saxpy` 的包放在名为 `app` 的目录下会生成 `app.shaders`,而工作区里每一个 `<something>/app/` 都声称拥有同一个模块。旧引擎下缺席,规则把缺席读作「沿用先前的推导」 |
 | `MCPP_PKG_NAMESPACE` *(2026.9.7.1+)* | -- | `[package] namespace`。包未声明命名空间时为空。需要产出在索引范围内唯一的名字的规则用这一对而不是单用名字,因为包身份是 `(namespace, name)` |
 | `MCPP_DEVICE_SOURCES` *(2026.9.5.2+)* | `mcpp::device_sources()` | 本包有效 `sources` 匹配到的设备类源文件(`.cu`、`.hip`…),相对包根,一行一个;没有时为空串。引擎一个都不编译 —— 由本程序引入的规则包把每一个变成一条 `mcpp::action`。已经过收窄:构建未覆盖的 `{ glob, accel }` 条目贡献为空,因此 `--no-accel` 得到空列表 |
 | `MCPP_OUT_DIR` | `mcpp::out_dir()` | mcpp 提供的可写输出/暂存目录 |