• libltdl/m4/libtool.m4 (_LT_PROG_AR): New macro, detect the

interface used by the archiver. In particullar, add the AR_SEP
variable to allow archivers that does not allow a space between
the options to create an archive and the archive name and the
ar_extract_one_by_one variable which indicates if the archiver
can extract all members in one go.

• libltdl/m4/libtool.m4: Add $AR_SEP between $AR_FLAGS and the

archive file name in all $AR commands.

• libltdl/config/ltmain.m4sh (func_extract_an_archive): Add support

for archivers that only supports extracting one member at a time
and otherwise adjust to the above libtool.m4 changes. Also, add
$AR_SEP to the $AR invocations.

• Makefile.am: Pass AR, AR_FLAGS and AR_SEP through to the

testsuite.

• tests/archive-in-archive.at: Extract archive name from the .la

file instead of hardcodeing the name, and allow different archivers.