libtool 2.4 args parsing incredibly slow

[Dan McGee]

Hadn't noticed this regression until I was running some things on my
slower Atom laptop today, but thought I'd let you guys know what we're
seeing in our test suite. The project is pacman
(http://projects.archlinux.org/pacman.git/), the Arch Linux package
manager. I've tried to put together a small test case to show the
difference; a tarball is attached. Extract it and copy your /bin/echo
to .libs/lt-echo and it should work.

I'm noticing the super slow argument parsing when invoking the wrapper
script during our test runs. This particular test is meant to provide
1000 test packages as arguments; it performs fine on our maint branch
but takes forever on master now due to a libtool upgrade.

Here is the output of my test harness/script:

$ ./time-test.sh
no wrapper:

real    0m0.038s
user    0m0.033s
sys     0m0.003s
libtool 1.5 wrapper:

real    0m0.174s
user    0m0.157s
sys     0m0.020s
libtool 2.4 wrapper:

real    1m0.118s
user    0m59.806s
sys     0m0.077s

If the attachment does not come through or it is stripped, it is
available here for now as well:
http://dev.archlinux.org/~dan/lt-args-regression.tar.gz

-Dan

lt-args-regression.tar.gz
Description: GNU Zip compressed data