Add feature to enable passing variable from command line when calling xmake build

[tie-pilot-qxw]

Is your feature request related to a problem? Please describe.

I'm binding C++ code to Rust, and since templates can't be passed across languages, I need to decide which template to use when calling xmake build from the Rust code. I want the add_defines function to accept a command-line variable, allowing me to select the template at compile time. Currently, I'm using environment variables as a workaround, but this approach feels redundant and may have potential issues. I'd like to optimize this process.

Describe the solution you'd like

Maybe the build script should be able to accept optional variables from the command line, such as:

// this is the build script
local a = input() or ...

// this is the command line
xmake build --var "a=123" [target]

Describe alternatives you've considered

No response

Additional context

No response

[waruqi]

use the custom option.

https://xmake.io/#/manual/configuration_option

xmake f --xxx=123
xmake build

[tie-pilot-qxw]

Thanks a lot! That worked.