grep @3.7.2+universal fails to build on M1 Mac

[hmeine (Hans Meine)]

This is my first MacPorts installation on Apple silicon.

sudo port clean grep
sudo port install grep +universal

fails with

--->  Attempting to fetch grep-3.7_2+universal.darwin_21.arm64-x86_64.tbz2 from https://fra.de.packages.macports.org/grep
--->  Attempting to fetch grep-3.7_2+universal.darwin_21.arm64-x86_64.tbz2 from https://nue.de.packages.macports.org/grep
--->  Attempting to fetch grep-3.7_2+universal.darwin_21.arm64-x86_64.tbz2 from https://packages.macports.org/grep
--->  Fetching distfiles for grep
--->  Verifying checksums for grep
--->  Extracting grep
--->  Configuring grep
Error: Failed to configure grep: consult /opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_sysutils_grep/grep/work/grep-3.7/config.log

The configure error seems to be

configure:46378: error: Cannot find a type to use in place of socklen_t

and looks very similar to what was reported for m4 in #62991. I don't know what a "muniversal port group" is, yet, and whether a similar fix could apply here.

[ryandesign (Ryan Carsten Schmidt)]

A portgroup is like an include file. It contains commonly-needed functionality that can be included by reference in any portfile that needs it.

The muniversal portgroup contains code that replaces the standard MacPorts universal variant (which builds for all architectures at the same time by using multiple -arch flags in a single build) with a merged universal variant (which configures and builds separately for each architecture and then merges the results with lipo).

Duplicate of #64135.