Version 2.2_rc5 of sys-apps/portage adds support for EAPI=”2_pre1″ which has some changes in conditional USE dependency syntax. The previous experimental EAPI=”2_pre0″ value is no longer supported.
For more information about experimental EAPI features, refer to bug #233213 and also see the “Ebuild” chapter of the html documentation that is installed with portage when USE=doc is enabled. I’ve posted a copy of the EAPI=”2_pre1″ documentation here:
EAPI 2_pre1 Helpers doman Language codes in file names are now used for path translation. Table 6.1. Man Page Path Translation Source Destination foo.1 /usr/share/man/man1/foo.1 foo.lang.1 /usr/share/man/lang/man1/foo.1 USE Dependencies Unconditional USE Dependencies Table 6.2. Syntax Examples Example Meaning foo[bar] foo must have bar enabled foo[bar,baz] foo must have both bar and baz enabled foo[-bar,baz] foo must have bar disabled and baz enabled Conditional USE Dependencies Table 6.3. Syntax Examples Compact Form Equivalent Expanded Form foo[bar?] bar? ( foo[bar] ) !bar? ( foo ) foo[!bar?] bar? ( foo ) !bar? ( foo[-bar] ) foo[bar=] bar? ( foo[bar] ) !bar? ( foo[-bar] ) foo[!bar=] bar? ( foo[-bar] ) !bar? ( foo[bar] )