Update to 2.4.6.

See
https://www.wireshark.org/docs/relnotes/wireshark-2.4.6.html for a list of
changes in this release.

Additionally, fix the following issues in the Makefile [1]:

• Add missing --with-* for lz4, snappy, and nghttp2
• Remove obsolete --with-* for IPv6 and gcrypt
• Use localbase

PR: 227131 [1]
Submitted by: Greg V <greg@unrelenting.technology> [1]