fping v5.5

New features

• New option -J / --json for JSON output. See doc/fping-json.md for
  the JSON schema. This feature is still in alpha and the schema
  might change in future releases (#386, thanks @bonkf,
  @JoshIPT, @sebast-gsnw, and @auerswal).
• The -g, --generate option now also supports IPv6 addresses (#376,
  thanks @auerswal)
• New option --seqmap-timeout to control the time after which sequence
  numbers can be used again (#388, thanks @auerswal)

Bugfixes and other changes

• Fix OpenBSD sprintf() warning (#394, thanks @gsnw-sebast)
• Fix fallback to SO_TIMESTAMP if SO_TIMESTAMPNS is not available (#375,
  thanks @auerswal)
• When reading target names from file or standard input, lines longer
  than the static buffer are no longer interpreted as more than one line
  (#378, thanks @auerswal)
• Typo fix in error message when SO_BINDTODEVICE fails
• Options --print-tos and --print-ttl now also work for IPv6, and no
  longer require privileges (#384, thanks @auerswal)
• Report received ICMPv6 error messages (#391, thanks @auerswal)
• Suppress duplicate reports in count mode with -q, --quiet or -Q, --squiet
  (#392, thanks @gsnw-sebast and @auerswal)
• Switch to alpine-based multi-stage Docker build to reduce image size
  and improve build performance; add OpenContainers-compatible labels
  (#399, thanks @hoodadt)
• Print receive ping moved to new functions (#400, thanks @gsnw-sebast)
• Avoid unsigned overflow when determining the memory size to save
  response times on systems where size_t is the same as unsigned int
  (#412 by @auerswal)
• Document the new minimum value for the -p option (#414, thanks @auerswal)
• Fix build without IPv6 support (#416, thanks @auerswal)
• Fix debug build use of dbg_printf in fping.c (#415, thanks @auerswal)
• Remove MacOS-specific test for -I option (#407)
• GitHub Actions fixes (thanks @gsnw-sebast)
• Fix measurement of time for timed reports (-Q) to start after DNS name
  resolution.
• Updated autoconf from 2.71 to 2.72
• Updated automake from 1.16.5 to 1.18.1
• Updated libtool from 2.4.6 to 2.5.4
• Implemented verification of autotools tarballs in Github actions.
• Implemented stricter flag value checking (e.g. -c 10xyz is not accepted anymore).