irssi: add patch to fix static linking

irssi: add patch to fix static linking

An upstream change which removed the option to build Irssi without SSL
support (v1.0.0 and later) also eliminated the use of PKG_CHECK_MODULES
to find the OpenSSL library, relying only on a test with AC_CHECK_LIB
for that purpose.

This unfortunately broke static linking since the flag to link with
zlib, used by OpenSSL, is missed completely.

The newly added patch therefore adds PKG_CHECK_MODULES back into the
configure script.

Fixes:

  http://autobuild.buildroot.net/results/e8b51f65525246d1205a26859d418393aaebf48c/
  http://autobuild.buildroot.net/results/35d952b3b36e295723bf8ed1badb4c9439201822/
  http://autobuild.buildroot.net/results/ea8af1458edf3ce0e2b1c444d2ae29ac1e5d2fbf/
  [...]

Signed-off-by: Rodrigo Rebello <rprebello@gmail.com>
Reviewed-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>