boost fails to build on Mac OS X Lion

[RobK88]

I am unable to build boost on my old Mac running Lion. Macports is configured to use libc++.

--->  Computing dependencies for boost
--->  Configuring boost
--->  Building boost
Error: Failed to build boost: command execution failed
Error: See /opt/local/var/macports/logs/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_devel_boost/boost/main.log for details.
Error: rev-upgrade failed: Error rebuilding boost
Error: Follow https://guide.macports.org/#project.tickets to report a bug.

I have also tried to upgrade boost using the following commands without success:

sudo port clean boost
sudo port upgrade boost configure.compiler=clang

I finally ran the following upgrade command with the verbose option: sudo port -v upgrade boost

Attached please find the output of the command. I also have attached the main.log file.

P.S. As recommended, I have removed the default.compilers line from macports.conf for Macports 2.6.x

[RobK88]

P.S. I forgot to mention that the following ports are now broken on my Mac because boost failed to build:

Scanning binaries for linking errors
--->  Found 34 broken files, matching files to ports     
--->  Found 4 broken ports, determining rebuild order
You can always run 'port rev-upgrade' again to fix errors.
The following ports will be rebuilt:
 boost @1.71.0+no_single+no_static+python27
 harfbuzz-icu @2.6.2
 texlive-bin @2019.50896+x11
 raptor2 @2.0.15

[jmroot (Joshua Root)]

#59388