Finer build time dependencies to optimize sysroot preparation time

Hello everyone,

I'm trying to solve the following problem (I'm using the latest scarthgap release):
- I have a recipe A whose job is to aggregate libraries produced by multiple recipes (basically aggregate a bunch of static libraries into a shared one to reduce the file system size).
- Right now, I added the list of recipes into the "DEPENDS" variable of recipe A. This works but this implies that all the files installed by the other recipes are copied into the sysroot of recipe A. The issue is that the other recipes package also header filers, source files, and other libraries, leading to slow downs in the build process (especially when ran under a static analysis tool).

I could have packaged the relevant files of the recipes into dedicated subpackages but the main recipe A can't depend on those packages (since only recipes can be used for build time dependencies).

Does someone have a proposal to work around this issue? Or maybe I need to redesign this "aggregation" recipe?

Thank you in advance.