coinmp: actually link the libraries

Several people named Chris report failures in the solver unit test, and
apparently the CoinMP libraries have loads of unresolved symbols
because they don't have NEEDED entries, i.e. were not linked properly;
let's see if this fixes it.

Change-Id: Id406e14b0805a458d608c23cb7c65d873b5ba2f0
Reviewed-on: https://gerrit.libreoffice.org/8850
Reviewed-by: Chris Laplante <mostthingsweb@gmail.com>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>
(cherry picked from commit 6731f6c36faf64ab4522f0ffe2045c794849fabe)
Fix Windows build(external/coinmp)

This patch fixes the problem that a linker misses CoinMP.dll.
The problem will occurs when we use --enable-dbgutil option.

Reviewed-on: https://gerrit.libreoffice.org/8854
Reviewed-by: Matúš Kukan <matus.kukan@collabora.com>
Tested-by: Matúš Kukan <matus.kukan@collabora.com>
(cherry picked from commit cddbec75d402e260d6997ad69377346a8aa5774a)

Change-Id: If6cec0f9705db2af33cb9a69d9440e3053c5979a
Find apr and serf libraries in --enable-dbgutil Windows build.

Change-Id: I06af5605ac5cf8606864b7c42527aa567571341a
(cherry picked from commit 702d79a3f8fd3c5e4b433195908317075c87ad9d)
mpl-subset changes

Change-Id: Iebd435a40fb61ddb248d7bbb50f55b92b16f0141