perl-net-ssleay: fix configure

When TARGET_LDFLAGS contains more than one option, the generated
Makefile contains this definition of LDDLFLAGS:
        LDDLFLAGS = '--option-1 --option-2'

Which when passed to gcc is interpreted as a single option, and gcc
(rightfully) barfs on it, like with:
        arm-linux-gnueabihf-gcc: error: unrecognized command line
        option ‘-shared -g’

This is because perl-net-ssleay's buildsystem is really completely
brain-damaged. Other perl extensions do not behave like that, and
instead are doing the only sane thing to do: not add single quotes
around the definition, and just use what they were provided for
LDDLFLAGS.

So, just do the same for perl-net-ssleay. Since tweaking (yet once
more) their buildsystem is too complex, we just use a post-configure
hook to fix up the mess, by removing single quotes around the definition
of LDDLFLAGS.

Note: if only one option is specified, no single quotes are added,
but our hook is a no-op in this case.

See also:
    http://lists.busybox.net/pipermail/buildroot/2014-July/101782.html
and the previous message for even more entertainment. ;-)

Signed-off-by: Francois Perrad <francois.perrad@gadz.org>
[me: find the real cause of the issue, tweak the sed expression to not
 force -shared and instead just trim the single quotes, enhance commit
 log]
[Thomas: fix minor typos in the commit log, add comment above hook
 definition]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>