net/libproxy: update to 0.5.9

[vishwin]

Summary

Completely rewritten since 0.5.0. Plugin ports are gone, they are now built directly into the library

Test Plan

exp-run, then all consumers need bumped

[arrowd]

Are all these plugins compiled in statically? I don't see them in pkg-plist.

[arrowd]

net/libproxy/pkg-plist

9–70

Adding

DOCSDIR=	${PREFIX}/share/doc/${PORTNAME}-1.0
PORTDOCS=	*

allows to remove all these docs entries from the plist.

[vishwin]

In D48469#1106420, @arrowd wrote:

Are all these plugins compiled in statically? I don't see them in pkg-plist.

All internal now, hence "built directly into the library"

net/libproxy/pkg-plist

9–70

I prefer to declare them explicitly, since this is a build option after all, and wildcarding PORTDOCS also sometimes captures other artefacts