Knowledge Base:Overriding environment variables per package

Synopsis
The default environment variables during package builds are declared in, but sometimes you want to override a particular variable (like  or  ) for a single package.

Environment
This article is applicable to all Gentoo Linux installations.

Analysis
Portage supports per-package environment settings through and the  subdirectories.


 * Inside the directory, you create files that have the same syntax as  and give it a sensible name. The filename will be used as the key to override settings.
 * Inside the file, you tell which of these files will be used on a per-package basis

Resolution
First, create the directory structure. This one will host the files that contain the variable declarations we want to use:

Next, create the file(s) needed to override the settings. For instance, assume we need two specific overrides: one is for a package where we want to tweak the CFLAGS and FEATURES resulting in debug symbols to be built and the second one we want to update PORTAGE_TMPDIR as the package has a huge build storage requirement.

Finally, create or edit and point towards these override files for the specific packages:

Further Resources

 * /etc/portage/env on the Gentoo Wiki