xemacs: *** PANIC *** Configure tests are not working - compiler is broken.

[mouse07410 (Mouse)]

MacOS 10.15.7, Xcode-12.3.

$ sudo port install xemacs
Warning: You can install it as part of the Xcode Command Line Tools package by running `xcode-select --install'.
--->  Computing dependencies for xemacs
--->  Fetching archive for xemacs
--->  Attempting to fetch xemacs-21.4.22_17+sumo.darwin_19.x86_64.tbz2 from https://packages.macports.org/xemacs
--->  Attempting to fetch xemacs-21.4.22_17+sumo.darwin_19.x86_64.tbz2 from http://atl.us.packages.macports.org/xemacs
--->  Attempting to fetch xemacs-21.4.22_17+sumo.darwin_19.x86_64.tbz2 from https://cph.dk.packages.macports.org/xemacs
--->  Configuring xemacs
Error: Failed to configure xemacs, consult /opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_editors_xemacs/xemacs/work/xemacs-21.4.22/config.log
Error: Failed to configure xemacs: configure failure: command execution failed
Error: See /opt/local/var/macports/logs/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_editors_xemacs/xemacs/main.log for details.
Error: Follow https://guide.macports.org/#project.tickets to report a bug.
Error: Processing of port xemacs failed
$

In the log (full log attached):

version:1
:debug:sysinfo macOS 10.15 (darwin/19.6.0) arch i386
:debug:sysinfo MacPorts 2.6.4
:debug:sysinfo Xcode 12.3
:debug:sysinfo SDK 10.15
:debug:sysinfo MACOSX_DEPLOYMENT_TARGET: 10.15
.  .  .  .  .
:info:configure checking for gcc... /usr/bin/clang
:info:configure checking whether the C compiler (/usr/bin/clang -pipe -Os -std=gnu89 -isysroot/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk -arch x86_64 -L/opt/local/lib -Wl,-headerpad_max_install_names -Wl,-no_pie -Wl,-syslibroot,/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk -arch x86_64) works... yes
:info:configure checking whether the C compiler (/usr/bin/clang -pipe -Os -std=gnu89 -isysroot/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk -arch x86_64 -L/opt/local/lib -Wl,-headerpad_max_install_names -Wl,-no_pie -Wl,-syslibroot,/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk -arch x86_64) is a cross-compiler... no
:info:configure checking whether we are using GNU C... yes
:info:configure checking whether /usr/bin/clang accepts -g... yes
:info:configure checking how to run the C preprocessor... /usr/bin/clang -E
:info:configure checking for AIX... no
:info:configure checking for GNU libc... no
:info:configure Extracting information from the machine- and system-dependent headers...
:info:configure checking for buggy gcc versions... no
:info:configure checking for dynodump... no
:info:configure checking for malloc_set_state... no
:info:configure checking whether __after_morecore_hook exists... no
:info:configure checking for ranlib... ranlib -c
:info:configure checking for a BSD compatible install... /usr/bin/install -c
:info:configure checking for bison... bison -y
:info:configure checking for a.out.h... no
.  .  .  .  .
:info:configure checking whether struct tm is in sys/time.h or time.h... time.h
:info:configure checking for tm_zone in struct tm... yes
:info:configure checking for working const... yes
:info:configure checking whether make sets ${MAKE}... yes
:info:configure checking whether byte ordering is bigendian... no
:info:configure checking size of short... 0
:info:configure *** PANIC *** Configure tests are not working - compiler is broken.
:info:configure *** PANIC *** Please examine config.log for compilation errors.
:info:configure Command failed:  cd "/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_editors_xemacs/xemacs/work/xemacs-21.4.22" && ./configure --prefix=/opt/local --mandir=/opt/local/share/man --without-postgresql --without-ldap --with-sound=none --pdump --site-prefixes=/opt/local --with-tty --with-dialogs=athena --with-widgets=athena --with-athena=3d --with-database=gdbm --with-mule 
:info:configure Exit code: 1
:error:configure Failed to configure xemacs, consult /opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_editors_xemacs/xemacs/work/xemacs-21.4.22/config.log
:error:configure Failed to configure xemacs: configure failure: command execution failed
:debug:configure Error code: NONE
:debug:configure Backtrace: configure failure: command execution failed

[mouse07410 (Mouse)]

main config log

[ryandesign (Ryan Carsten Schmidt)]

Duplicate of #61383.