Rather than setting them in the build profile, just set them in
etc/defaults.conf (overridable via etc/conf) to simplify the code.
- Also enable _FORTIFY_SOURCE=2 in CPPFLAGS.
- Also enable -z,relro in LDFLAGS.
As suggested by @chneukirchen.
- binutils updated to 2.25
- gcc updated to 4.9.2
- musl updated to 1.1.6
- kernel headers updated to 3.18.5
Also enable -fstack-protector-strong by default in the armv[67]hf-musl
cross profiles.