config: blacklist PORTAGE_BACKGROUND* vars

diff --git a/pym/portage/package/ebuild/_config/special_env_vars.py b/pym/portage/package/ebuild/_config/special_env_vars.py
index 6a196cfca2c4eada9ae1ccddfc061ce3a72d0182..4faa810f069fd497132ffd82a8c6152f4a12b0c2 100644 (file)
--- a/pym/portage/package/ebuild/_config/special_env_vars.py
+++ b/pym/portage/package/ebuild/_config/special_env_vars.py
@@ -8,12 +8,16 @@ __all__ = (
 
 import re
 
+# Blacklisted variables are internal variables that are never allowed
+# to enter the config instance from the external environment or
+# configuration files.
 env_blacklist = frozenset((
        "A", "AA", "CATEGORY", "DEPEND", "DESCRIPTION", "EAPI",
        "EBUILD_PHASE", "ED", "EMERGE_FROM", "EPREFIX", "EROOT",
        "HOMEPAGE", "INHERITED", "IUSE",
        "KEYWORDS", "LICENSE", "MERGE_TYPE",
-       "PDEPEND", "PF", "PKGUSE", "PORTAGE_BUILDIR_LOCKED",
+       "PDEPEND", "PF", "PKGUSE", "PORTAGE_BACKGROUND",
+       "PORTAGE_BACKGROUND_UNMERGE", "PORTAGE_BUILDIR_LOCKED",
        "PORTAGE_BUILT_USE", "PORTAGE_CONFIGROOT", "PORTAGE_IUSE",
        "PORTAGE_NONFATAL", "PORTAGE_REPO_NAME", "PORTAGE_SANDBOX_COMPAT_LEVEL",
        "PORTAGE_USE", "PROPERTIES", "PROVIDE", "RDEPEND", "RESTRICT",