Add recommendations for building linkers

[thesamesam]

We need a similar section to "What should you do when compiling compilers?" for linkers.

Noticed when looking at https://github.com/ossf/wg-best-practices-os-developers/pull/622.

Some initial candidates for GNU Binutils:

• --disable-default-execstack
• --enable-error-execstack
• --enable-relro
• --enable-secureplt (for ppc)
• --enable-textrel-check=error
• --enable-separate-code / --enable-rosegment (although do see https://github.com/ossf/wg-best-practices-os-developers/issues/588#issuecomment-2312549337)

[david-a-wheeler]

+1, makes sense to me. Would you be willing to create a first draft pull request?

[thesamesam]

Happily, will do.