自动识别 clang 的 target

[KeqingMoe]

你在什么场景下需要该功能？

自从 830e65800 起，使用 llvm-mingw 必须手动 xmake f -p mingw 或 xmake.lua 中写上 set_plat("mingw") ，否则一律会将 --target=x86_64-windows-msvc 传递给 clang，然而期待的是 --target=x86_64-w64-windows-gnu。

#6059 也提到了这个问题。

描述可能的解决方案

一个简单但未必足够好的实现方式是，编译前先运行 clang -v ，可能的输出：

clang version 19.1.3 (https://github.com/llvm/llvm-project.git ab51eccf88f5321e7c60591c5546b254b6afab99)
Target: x86_64-w64-windows-gnu
Thread model: posix
InstalledDir: C:/****/llvm-mingw-20241030-ucrt-x86_64/bin

从第二行的 Target: 之后开始提取出 x86_64-w64-windows-gnu ，然后再视情况做后续处理。

描述你认为的候选方案

No response

其他信息

No response

[Issues-translate-bot]

Bot detected the issue body's language is not English, translate it automatically.

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Title: Automatically identify clang’s target

In what scenario do you need this function?

Since 830e65800, using llvm-mingw must manually xmake f -p mingw or write in xmake.lua set_plat("mingw"), otherwise --target=x86_64-windows-msvc will always be passed to clang, but what is expected is --target=x86_64-w64-windows-gnu.

#6059 also mentions this issue.

Describe possible solutions

A simple but not necessarily good enough implementation is to run clang -v before compiling. Possible output:

clang version 19.1.3 (https://github.com/llvm/llvm-project.git ab51eccf88f5321e7c60591c5546b254b6afab99)
Target: x86_64-w64-windows-gnu
Thread model: posix
InstalledDir: C:/****/llvm-mingw-20241030-ucrt-x86_64/bin

Start extracting x86_64-w64-windows-gnu after Target: in the second line, and then perform subsequent processing as appropriate.

Describe your alternatives

No response

Other information

No response

[waruqi]

@star-hengxing 话说当初显式指定 target 是解决啥问题？不设置 直接走默认 target 不行么

[Issues-translate-bot]

Bot detected the issue body's language is not English, translate it automatically.

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@star-hengxing What problem was solved by explicitly specifying the target? Isn’t it okay to just use the default target without setting it?

[star-hengxing]

target 名已经修了 #5973

@star-hengxing 话说当初显式指定 target 是解决啥问题？不设置 直接走默认 target 不行么

clang 本身是交叉编译工具链，如果默认 target 是 x86_64-windows-msvc 或者在非 msys2 之类的开发环境，想用 mingw + clang 就要显式给出 target & sysroot 。但 mingw 的 sysroot 头文件有 include 的问题（好像只是 msys2 的问题？）就删了，只留下 target，理论上应该没有大碍。
#5823 (comment)