Eu instalei o aptitude e obtive as soluções propostas:
$ sudo aptitude install makerware
The following NEW packages will be installed:
avrdude{a} conveyor{a} conveyor-common{a} conveyor-ui{a} libarmadillo4{a}
libarpack2{a} libboost-program-options1.54.0{a} libcoin80{a} libdap11{a}
libdapclient3{a} libdigitizer{a} libepsilon1{a} libfreexl1{a} libftdi1{a}
libgdal1h{a} libgeos-3.4.2{a} libgeos-c1{a} libgraphicsmagick3{a}
libhdf4-0-alt{a} libhdf5-7{a} libjsoncpp0{a} libkml0{a} libmbqtutils{a}
libmysqlclient18{a} libnetcdfc7{a} libogdi3.2{a} libopenmesh-3.2{a}
libopenscenegraph99{a} libopenthreads14{a} libpq5{a} libproj0{a}
libqt5multimedia5{ab} libqt5multimediawidgets5{a} libspatialite5{a}
libthing{a} libtinything{a} libtoolpathviz{a} liburiparser1{a}
libxerces-c3.1{a} libxine2{a} libxine2-bin{a} libxine2-doc{a}
libxine2-ffmpeg{a} libxine2-misc-plugins{a} libxine2-plugins{a}
makerbot-driver{a} makerware mb-libjsonrpc{a} mb-libopencv2.4{a}
mb-libstdc++6{a} mb-libvtk5.10{a} mb-pyserial{a} miracle-grue{a}
mysql-common{a} proj-bin{a} proj-data{a}
0 packages upgraded, 56 newly installed, 0 to remove and 0 not upgraded.
Need to get 206 MB/206 MB of archives. After unpacking 340 MB will be used.
The following packages have unmet dependencies:
libqt5multimedia5 : Depends: qtbase-abi-5-2-1 which is a virtual package.
The following actions will resolve these dependencies:
Keep the following packages at their current version:
1) libqt5multimedia5 [Not Installed]
2) libqt5multimediawidgets5 [Not Installed]
3) makerware [Not Installed]
Accept this solution? [Y/n/q/?] n
The following actions will resolve these dependencies:
Remove the following packages:
1) libqt5help5
2) libqt5xmlpatterns5
3) musescore
4) qml-module-qtquick-localstorage
5) qml-module-qtquick-window2
6) qml-module-qtquick2
7) qml-module-qtwebkit
Install the following packages:
8) libqt5positioning5 [5.2.1-1ubuntu2 (now, trusty)]
9) libqt5sensors5 [5.2.1+dfsg-2ubuntu2 (now, trusty)]
Downgrade the following packages:
10) libqt5clucene5 [5.3.0-5~trusty1 (now, trusty) -> 5.2.1-8build1 (trusty)]
11) libqt5core5a [5.3.0+dfsg-2ubuntu9~trusty1 (now, trusty) -> 5.2.1+dfsg-1u
12) libqt5dbus5 [5.3.0+dfsg-2ubuntu9~trusty1 (now, trusty) -> 5.2.1+dfsg-1ub
13) libqt5gui5 [5.3.0+dfsg-2ubuntu9~trusty1 (now, trusty) -> 5.2.1+dfsg-1ubu
14) libqt5network5 [5.3.0+dfsg-2ubuntu9~trusty1 (now, trusty) -> 5.2.1+dfsg-
15) libqt5opengl5 [5.3.0+dfsg-2ubuntu9~trusty1 (now, trusty) -> 5.2.1+dfsg-1
16) libqt5printsupport5 [5.3.0+dfsg-2ubuntu9~trusty1 (now, trusty) -> 5.2.1+
17) libqt5qml5 [5.3.0-3ubuntu13~trusty1 (now, trusty) -> 5.2.1-3ubuntu15.1 (
18) libqt5quick5 [5.3.0-3ubuntu13~trusty1 (now, trusty) -> 5.2.1-3ubuntu15.1
19) libqt5sql5 [5.3.0+dfsg-2ubuntu9~trusty1 (now, trusty) -> 5.2.1+dfsg-1ubu
20) libqt5sql5-sqlite [5.3.0+dfsg-2ubuntu9~trusty1 (now, trusty) -> 5.2.1+df
21) libqt5svg5 [5.3.0-2~trusty1 (now, trusty) -> 5.2.1-1 (trusty)]
22) libqt5test5 [5.3.0+dfsg-2ubuntu9~trusty1 (now, trusty) -> 5.2.1+dfsg-1ub
23) libqt5webkit5 [5.3.0+dfsg-1ubuntu2~trusty1 (now, trusty) -> 5.1.1-1ubunt
24) libqt5webkit5-qmlwebkitplugin [5.3.0+dfsg-1ubuntu2~trusty1 (now, trusty)
25) libqt5widgets5 [5.3.0+dfsg-2ubuntu9~trusty1 (now, trusty) -> 5.2.1+dfsg-
26) libqt5xml5 [5.3.0+dfsg-2ubuntu9~trusty1 (now, trusty) -> 5.2.1+dfsg-1ubu
27) qtdeclarative5-localstorage-plugin [5.3.0-3ubuntu13~trusty1 (now, trusty
28) qtdeclarative5-qtquick2-plugin [5.3.0-3ubuntu13~trusty1 (now, trusty) ->
29) qtdeclarative5-window-plugin [5.3.0-3ubuntu13~trusty1 (now, trusty) -> 5
Accept this solution? [Y/n/q/?]
Parece que, quando adicionei o repositório do MuseScore e atualizei o MuseScore para o 2.0, ele também atualizou o qt para o 5.3, o que parece ser incompatível com o Makerware.
Por enquanto, parece que tenho que rebaixar o MuseScore ou não usar o Makerware.