Gentoo Packages

We have just added (for all arches except arm and mips, these follow later) a new set of profiles with release version 17.0 to the Gentoo repository. These bring three changes: 1) The default C++ language version for applications is now C++14.

 This change is mostly relevant to Gentoo developers. It also
 means, however, that compilers earlier than GCC 6 are masked 
 and not supported for use as a system compiler anymore. Feel 
 free to unmask them if you need them for specific applications.

2) Where supported, GCC will now build position-independent

 executables (PIE) by default. This improves the overall
 security fingerprint. The switch from non-PIE to PIE binaries,
 however, requires some steps by users, as detailed below.

3) Up to now, hardened profiles were separate from the default

 profile tree. Now they are moving into the 17.0 profile
 as a feature there, similar to "no-multilib" and "systemd".

Please migrate away from the 13.0 profiles within the six weeks after GCC 6.4.0 has been stabilized on your architecture. The 13.0 profiles will be deprecated then and removed in half a year.

If you are not already running a hardened setup with PIE enabled, then switching the profile involves the following steps: If not already done,

• Use gcc-config to select gcc-6.4.0 or later as system compiler
• Re-source /etc/profile: . /etc/profile
• Re-emerge libtool emerge -1 sys-devel/libtool

Then,

• Select the new profile with eselect
• Re-emerge, in this sequence, gcc, binutils, and glibc emerge -1 sys-devel/gcc:6.4.0 emerge -1 sys-devel/binutils emerge -1 sys-libs/glibc
• Rebuild your entire system emerge -e @world

Switching the profile from 13.0 to 17.0 modifies the settings of GCC 6 to generate PIE executables by default; thus, you need to do the rebuilds even if you have already used GCC 6 beforehand. If you do not follow these steps you may get spurious build failures when the linker tries unsuccessfully to combine non-PIE and PIE code.