rtld: Sync 6/7 - Minimize differences from FreeBSD

rtld: Sync 6/7 - Minimize differences from FreeBSD

DragonFly developed some rtld features before FreeBSD, and consequently
those features were ported back to FreeBSD.  Some portions of these
new lines were modified for various reasons, e.g. the variable names
weren't liked or additional constraints were deemed necessary such as
the ability to maintain the old (incorrect) behavior of RUNPATH.

In any case, there were minor differences including whitespace, and
this commit reduces those differences to ease future syncing.