feat: auto-detect MSVC outside VS shell

[peter-jerry-ye]

Summary

• keep the existing PATH-based native compiler detection for cl, cc, gcc, and clang
• on Windows, if none of those are available on PATH, use find-msvc-tools to discover cl.exe
• capture the discovered MSVC environment and replay it only for the native C commands that need it
• keep the scope narrow by threading only fallback native link syntax into build_plan
• update docs, shell completion snapshots, and Windows CI to reflect the new default workflow

Why

Windows users should be able to build native targets without starting from a Visual Studio Developer Command Prompt.

Scope

• explicit compiler overrides still win
• PATH-based detection still wins when available
• the MSVC environment overlay is only used for the auto-detected default MSVC toolchain
• the change is isolated to native toolchain auto-detection and native C command execution

[semanticdiff-com]

Review changes with  

Changed Files

File	Status
crates/moonbuild-rupes-recta/src/build_lower/compiler/link_core.rs	58% smaller
crates/moonbuild-rupes-recta/src/build_plan/builders.rs	37% smaller
crates/moonbuild-rupes-recta/src/build_lower/lower_aux.rs	29% smaller
crates/moonbuild-rupes-recta/src/build_lower/lower_build.rs	21% smaller
crates/moonbuild-rupes-recta/src/compile/mod.rs	12% smaller
crates/moonbuild-rupes-recta/src/build_lower/context.rs	9% smaller
crates/moonutil/src/compiler_flags.rs	2% smaller
crates/moonbuild-rupes-recta/src/build_lower/mod.rs	2% smaller
.github/workflows/ci.yml	0% smaller
Cargo.lock	Unsupported file format
crates/moon/src/cli/snapshots/shell_completion_bash.stdout	Unsupported file format
crates/moon/src/cli/snapshots/shell_completion_elvish.stdout	Unsupported file format
crates/moon/src/cli/snapshots/shell_completion_fish.stdout	Unsupported file format
crates/moon/src/cli/snapshots/shell_completion_powershell.stdout	Unsupported file format
crates/moon/src/cli/snapshots/shell_completion_zsh.stdout	Unsupported file format
crates/moon/src/cli/tool.rs	0% smaller
crates/moon/src/cli/tool/env_exec.rs	0% smaller
crates/moonbuild-rupes-recta/Cargo.toml	Unsupported file format
crates/moonbuild-rupes-recta/src/build_plan/mod.rs	0% smaller
crates/moonutil/Cargo.toml	Unsupported file format
docs/dev/reference/native-c-toolchain-resolution.md	Unsupported file format

[chatgpt-codex-connector]

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Reviewed commit: dddfc109de

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[chatgpt-codex-connector]

Honor explicit compiler overrides before forcing MSVC

The new early return in DETECTED_CC makes cl.exe win whenever Visual Studio is installed, even if users set MOON_CC to a GCC/Clang toolchain. In this repo, propagate_link_config still consults DETECTED_CC when native.cc is unset (crates/moonbuild-rupes-recta/src/build_plan/builders.rs:1029), so this change can now emit MSVC-style link args (foo.lib, /LIBPATH:) while the actual compiler is non-MSVC, breaking native linking for mixed/MinGW setups that previously worked unless cl was already on PATH.

Useful? React with 👍 / 👎.

[tonyfettes]

Confirmed:

$env:MOON_CC="clang"
moon test -v

failed: clang -o C:\Users\mbt\Workspace\tonyfettes-raylib\_build\native\debug\test\internal\raylib\raylib.blackbox_test.exe -IC:\Users\mbt\.moon\include -g -fwrapv -fno-strict-aliasing -Wno-unused-value C:\Users\mbt\Workspace\tonyfettes-raylib\_build\native\debug\test\internal\raylib\raylib.blackbox_test.c C:\Users\mbt\Workspace\tonyfettes-raylib\_build\native\debug\test\runtime.obj C:\Users\mbt\Workspace\tonyfettes-raylib\_build\native\debug\test\internal\raylib\libraylib.lib -lm opengl32.lib gdi32.lib winmm.lib user32.lib shell32.lib opengl32.lib gdi32.lib winmm.lib user32.lib shell32.lib
clang: error: no such file or directory: 'opengl32.lib'
clang: error: no such file or directory: 'gdi32.lib'
clang: error: no such file or directory: 'winmm.lib'
clang: error: no such file or directory: 'user32.lib'
clang: error: no such file or directory: 'shell32.lib'

[peter-jerry-ye]

This should have been fixed.

[tonyfettes]

Compile and link correctly on Windows when MSVC is configured but not added to path.

Reproduced the bug spotted by Codex. See above for more information.