lz4 @1.9.3: does not build universal with arm64/x86_64 ./gen_manual: Bad CPU type in executable

[kencu (Ken)]

it probably doesn't build arm64 at all, but this is a universal build on a BigSur Intel system:

/usr/bin/clang++  -Os -stdlib=libc++ -arch arm64  gen_manual.cpp -o gen_manual
make[1]: Entering directory `/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_archivers_lz4/lz4/work/lz4-1.9.3-arm64/tests'
/usr/bin/clang -c -Os -arch arm64 -I../lib -I../programs -DXXH_NAMESPACE=LZ4_ ../lib/lz4.c -o lz4.o
/usr/bin/clang -c -Os -arch arm64 -I../lib -I../programs -DXXH_NAMESPACE=LZ4_ ../lib/lz4hc.c -o lz4hc.o
/usr/bin/clang -c -Os -arch arm64 -I../lib -I../programs -DXXH_NAMESPACE=LZ4_ ../lib/lz4frame.c -o lz4frame.o
/usr/bin/clang -c -Os -arch arm64 -I../lib -I../programs -DXXH_NAMESPACE=LZ4_ ../lib/xxhash.c -o xxhash.o
/usr/bin/clang -Os -arch arm64 -I../lib -I../programs -DXXH_NAMESPACE=LZ4_  -I../programs ../programs/datagen.c datagencli.c -o datagen
make[1]: Entering directory `/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_archivers_lz4/lz4/work/lz4-1.9.3-arm64/lib'
compiling static library
echo "Update lz4 manual in /doc"
echo "Update lz4frame manual in /doc"
Update lz4frame manual in /doc
Update lz4 manual in /doc
./gen_manual 1.9.3 ../../lib/lz4frame.h ../../doc/lz4frame_manual.html
make[1]: ./gen_manual: Bad CPU type in executable
./gen_manual 1.9.3 ../../lib/lz4.h ../../doc/lz4_manual.html
make[1]: ./gen_manual: Bad CPU type in executable
make[1]: *** [../../doc/lz4frame_manual.html] Error 1
make[1]: *** Waiting for unfinished jobs....
make[1]: *** [../../doc/lz4_manual.html] Error 1
make[1]: Leaving directory `/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_archivers_lz4/lz4/work/lz4-1.9.3-arm64/contrib/gen_manual'