- Make libcrypto.so position independent on i386.
- Enable linker error when libcrypto.so contains a relocation against text.
- Add "Do not modify" comment to generated source files.
- Set CC environment variable for Perl scripts to enable AVX instructions.
- Update __FreeBSD_version to indicate libcrypto.so is position independent.

Note this is a direct commit because head has OpenSSL 1.0.2 branch but based
on r299389, r299462, r299464, r299479, and r299480.

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Merge OpenSSL 1.0.1c.

Approved by: benl (maintainer)