Improve the default installation policy

[waruqi]

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

The current logic for installing a target and its dependencies is confusing and inflexible.

We need to add an installation policy that gives users the flexibility to configure the installation themselves.

set_policy("install.targetdeps", true)
set_policy("install.targetdeps.runonly", true) -- default
set_policy("install.targetdeps.all", true)

For example:

app (binary) -> foo (shared) -> bar (static)

xmake install app

Only install the current target without deps

set_policy("install.targetdeps", false)

• Only Install app binary (add_installfiles, add_packages)
• Do not install any deps

Only install runonly target files (default)

set_policy("install.targetdeps.runonly", true) -- default

We just install the binary that can be run, and all the dynamic libraries needed to ensure that the binary can be run.

• Install app binary (add_installfiles, add_packages)
• Only install foo shared target file and package shared files (without add_headerfiles, add_installfiles)
• Do not install bar static target

Install target and it's all dep files

set_policy("install.targetdeps.all", true)

• Install app binary (add_installfiles, add_packages)
• install foo shared (with add_headerfiles, add_installfiles, add_packages)
• install bar static (with add_headerfiles, add_installfiles, add_packages)

Enable or disable to install package files

set_policy("install.targetpkgs", true) -- default
set_policy("install.targetpkgs", false)

It is also equivalent to xmake install --nopkgs app

https://github.com/xmake-io/xmake/issues/5308