Fail in a more informative way when required C++ standard is unsupported than `Invalid value for configure.compiler`

[barracuda156]

Someone tried to build FTXUI on Leopard and got this failure, which, I admit, is unnecessarily confusing:

:debug:clean Fetching FTXUI-5.0.0_0.darwin_9.ppc.tbz2 archive size
:debug:clean Searching for dependency: gcc7
:debug:clean Found Dependency: receipt exists for gcc7
:debug:clean Searching for dependency: libgcc
:debug:clean Found Dependency: receipt exists for libgcc
:info:clean .:debug:clean tree-sitter has no conflicts
:debug:clean Fetching tree-sitter-0.24.3_0.darwin_9.ppc.tbz2 archive size
:info:clean .:debug:clean tree-sitter-cpp has no conflicts
:debug:clean Fetching tree-sitter-cpp-0.23.4_0.darwin_9.ppc.tbz2 archive size
:debug:clean Searching for dependency: legacy-support
:debug:clean Found Dependency: receipt exists for legacy-support
:debug:main Executing org.macports.main (step-writer)
:debug:main dropping privileges: euid changed to 502, egid changed to 500.
:debug:main Privilege de-escalation not attempted as not running as root.
:debug:archivefetch archivefetch phase started at Sun Nov 17 12:46:01 EST 2024
:msg:archivefetch --->  Fetching archive for step-writer
:debug:archivefetch Executing org.macports.archivefetch (step-writer)
:debug:archivefetch euid/egid changed to: 0/0
:debug:archivefetch chowned /opt/local/var/macports/incoming to macports
:debug:archivefetch euid/egid changed to: 502/500
:info:archivefetch --->  step-writer-2024.11.16_0.darwin_9.ppc.tbz2 doesn't seem to exist in /opt/local/var/macports/incoming/verified
:msg:archivefetch --->  Attempting to fetch step-writer-2024.11.16_0.darwin_9.ppc.tbz2 from http://packages.macports.org/step-writer
:debug:archivefetch Fetching archive failed: The requested URL returned error: 404
:msg:archivefetch --->  Attempting to fetch step-writer-2024.11.16_0.darwin_9.ppc.tbz2 from http://bos.us.packages.macports.org/step-writer
:debug:archivefetch Fetching archive failed: The requested URL returned error: 404
:msg:archivefetch --->  Attempting to fetch step-writer-2024.11.16_0.darwin_9.ppc.tbz2 from https://mirrors.mit.edu/macports/packages/step-writer
:debug:archivefetch Fetching archive failed: error:1407742E:SSL routines:SSL23_GET_SERVER_HELLO:tlsv1 alert protocol version
:debug:archivefetch Privilege de-escalation not attempted as not running as root.
:debug:fetch fetch phase started at Sun Nov 17 12:46:10 EST 2024
:notice:fetch --->  Fetching distfiles for step-writer
:debug:fetch elevating privileges for fetch: euid changed to 0, egid changed to 0.
:debug:fetch dropping privileges: euid changed to 502, egid changed to 500.
:debug:fetch Executing org.macports.fetch (step-writer)
:info:fetch --->  step-writer-15b02568f7ec731215eb717b076a77f61e6e080a.tar.gz does not exist in /opt/local/var/macports/distfiles/step-writer
:notice:fetch --->  Attempting to fetch step-writer-15b02568f7ec731215eb717b076a77f61e6e080a.tar.gz from https://github.com/BrianAnakPintar/step-writer/archive/15b02568f7ec731215eb717b076a77f61e6e080a
:debug:fetch Fetching distfile failed: error:1407742E:SSL routines:SSL23_GET_SERVER_HELLO:tlsv1 alert protocol version
:notice:fetch --->  Attempting to fetch step-writer-15b02568f7ec731215eb717b076a77f61e6e080a.tar.gz from https://mirrors.mit.edu/macports/distfiles/step-writer
:debug:fetch Fetching distfile failed: error:1407742E:SSL routines:SSL23_GET_SERVER_HELLO:tlsv1 alert protocol version
:notice:fetch --->  Attempting to fetch step-writer-15b02568f7ec731215eb717b076a77f61e6e080a.tar.gz from http://mirror.fcix.net/macports/distfiles/step-writer
:debug:fetch Privilege de-escalation not attempted as not running as root.
:debug:checksum checksum phase started at Sun Nov 17 12:46:19 EST 2024
:notice:checksum --->  Verifying checksums for step-writer
:debug:checksum Executing org.macports.checksum (step-writer)
:info:checksum --->  Checksumming step-writer-15b02568f7ec731215eb717b076a77f61e6e080a.tar.gz
:debug:checksum Calculated (rmd160) is 5fda1b912f6fd64a5549527ff50a229438bd3c1d
:debug:checksum Correct (rmd160) checksum for step-writer-15b02568f7ec731215eb717b076a77f61e6e080a.tar.gz
:debug:checksum Calculated (sha256) is faa3470e81de0f7ed16faddf10560689d340cad07bcd9f325a8c32f0e2cccc26
:debug:checksum Correct (sha256) checksum for step-writer-15b02568f7ec731215eb717b076a77f61e6e080a.tar.gz
:debug:checksum Calculated (size) is 21276422
:debug:checksum Correct (size) checksum for step-writer-15b02568f7ec731215eb717b076a77f61e6e080a.tar.gz
:debug:checksum Privilege de-escalation not attempted as not running as root.
:debug:extract extract phase started at Sun Nov 17 12:46:20 EST 2024
:notice:extract --->  Extracting step-writer
:debug:extract Executing org.macports.extract (step-writer)
:info:extract --->  Extracting step-writer-15b02568f7ec731215eb717b076a77f61e6e080a.tar.gz
:debug:extract setting option extract.args to '/opt/local/var/macports/distfiles/step-writer/step-writer-15b02568f7ec731215eb717b076a77f61e6e080a.tar.gz'
:debug:extract Environment: 
:debug:extract CC_PRINT_OPTIONS='YES'
:debug:extract CC_PRINT_OPTIONS_FILE='/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_editors_step-writer/step-writer/work/.CC_PRINT_OPTIONS'
:debug:extract CPATH='/opt/local/include'
:debug:extract DEVELOPER_DIR='/Developer'
:debug:extract LIBRARY_PATH='/opt/local/lib'
:debug:extract MACOSX_DEPLOYMENT_TARGET='10.5'
:debug:extract SOURCE_DATE_EPOCH='1731813880'
:info:extract Executing:  cd "/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_editors_step-writer/step-writer/work" && /usr/bin/gzip -dc '/opt/local/var/macports/distfiles/step-writer/step-writer-15b02568f7ec731215eb717b076a77f61e6e080a.tar.gz' | /usr/bin/gnutar --no-same-owner -xf - 
:debug:extract system:  cd "/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_editors_step-writer/step-writer/work" && /usr/bin/gzip -dc '/opt/local/var/macports/distfiles/step-writer/step-writer-15b02568f7ec731215eb717b076a77f61e6e080a.tar.gz' | /usr/bin/gnutar --no-same-owner -xf - 
:debug:extract euid/egid changed to: 0/0
:debug:extract chowned /opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_editors_step-writer/step-writer/work to macports
:debug:extract euid/egid changed to: 502/500
:debug:extract Privilege de-escalation not attempted as not running as root.
:debug:patch patch phase started at Sun Nov 17 12:46:21 EST 2024
:debug:patch Executing org.macports.patch (step-writer)
:notice:patch --->  Applying patches to step-writer
:info:patch --->  Applying patch-CMakeLists.diff
:debug:patch Environment: 
:debug:patch CC_PRINT_OPTIONS='YES'
:debug:patch CC_PRINT_OPTIONS_FILE='/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_editors_step-writer/step-writer/work/.CC_PRINT_OPTIONS'
:debug:patch CPATH='/opt/local/include'
:debug:patch DEVELOPER_DIR='/Developer'
:debug:patch LIBRARY_PATH='/opt/local/lib'
:debug:patch MACOSX_DEPLOYMENT_TARGET='10.5'
:debug:patch SOURCE_DATE_EPOCH='1731813880'
:info:patch Executing:  cd "/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_editors_step-writer/step-writer/work/step-writer-15b02568f7ec731215eb717b076a77f61e6e080a" && /usr/bin/patch -t -N -p0 < '/opt/local/var/macports/sources/rsync.macports.org/macports/release/tarballs/ports/editors/step-writer/files/patch-CMakeLists.diff'
:debug:patch system:  cd "/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_editors_step-writer/step-writer/work/step-writer-15b02568f7ec731215eb717b076a77f61e6e080a" && /usr/bin/patch -t -N -p0 < '/opt/local/var/macports/sources/rsync.macports.org/macports/release/tarballs/ports/editors/step-writer/files/patch-CMakeLists.diff'
:info:patch patching file CMakeLists.txt
:debug:patch Privilege de-escalation not attempted as not running as root.
:debug:configure configure phase started at Sun Nov 17 12:46:21 EST 2024
:notice:configure --->  Configuring step-writer
:error:configure Failed to configure step-writer: Invalid value for configure.compiler: 
:debug:configure Error code: NONE
:debug:configure Backtrace: Invalid value for configure.compiler: 
:debug:configure     while executing
:debug:configure "[ditem_key $ditem prerun] $targetname"
:error:configure See /opt/local/var/macports/logs/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_editors_step-writer/step-writer/main.log for details.

Perhaps it is not too difficult to display a message regarding a required C/C++ standard instead?