install problem with extensions

I am trying to build an extension, and I haveit installed on 2 machines,
but the ake install fails on a 3rd. Tow of the machines are Ubuntu 18.04,
and it installs fine on one, and fails on the other.

Here is the make install output:

stan(at)ica-db:~/src/pg-libphonenumber$ sudo make install
/bin/mkdir -p '/usr/lib/postgresql/11/lib'
/bin/mkdir -p '/usr/share/postgresql/11/extension'
/bin/mkdir -p '/usr/share/postgresql/11/extension'
/usr/bin/install -c -m 755 pg_libphonenumber.so
'/usr/lib/postgresql/11/lib/pg_libphonenumber.so'
/usr/bin/install -c -m 644 .//pg_libphonenumber.control
'/usr/share/postgresql/11/extension/'
/usr/bin/install -c -m 644 .//sql/pg_libphonenumber--*.sql
'/usr/share/postgresql/11/extension/'
/bin/mkdir -p '/usr/lib/postgresql/11/lib/bitcode/pg_libphonenumber'
/bin/mkdir -p '/usr/lib/postgresql/11/lib/bitcode'/pg_libphonenumber/src/
/usr/bin/install -c -m 644 src/error_handling.bc
'/usr/lib/postgresql/11/lib/bitcode'/pg_libphonenumber/src/
/usr/bin/install -c -m 644 src/pg_libphonenumber.bc
'/usr/lib/postgresql/11/lib/bitcode'/pg_libphonenumber/src/
/usr/bin/install -c -m 644 src/packed_phone_number.bc
'/usr/lib/postgresql/11/lib/bitcode'/pg_libphonenumber/src/
cd '/usr/lib/postgresql/11/lib/bitcode' && /usr/lib/llvm-6.0/bin/llvm-lto
-thinlto -thinlto-action=thinlink -o pg_libphonenumber.index.bc
pg_libphonenumber/src/error_handling.bc
pg_libphonenumber/src/pg_libphonenumber.bc
pg_libphonenumber/src/packed_phone_number.bc
error: can't create module summary index for buffer: Expected a single
module
LLVM ERROR: ThinLink didn't create an index
/usr/lib/postgresql/11/lib/pgxs/src/makefiles/pgxs.mk:229: recipe for
target 'install' failed
make: *** [install] Error 1

Can anyoine sygest where to look to resolve this error?

--
"They that would give up essential liberty for temporary safety deserve
neither liberty nor safety."
-- Benjamin Franklin