Build problem II

After trying in vain to build MuseScore under the Archlinux packagebuild system (see http://musescore.org/en/node/14123 no reply yet) I now tried building it under /usr/local
This gives me a new (different) error:
[ 23%] Building CXX object mscore/CMakeFiles/mscore.dir/exportxml.cpp.o
/usr/local/src/mscore-1.1/mscore/mscore/exportxml.cpp: In functie ‘void directionTag(Xml&, Attributes&, Element*)’:
/usr/local/src/mscore-1.1/mscore/mscore/exportxml.cpp:2366:59: fout: invalid conversion from ‘const SLine*’ to ‘SLine*’ [-fpermissive]
make[3]: *** [mscore/CMakeFiles/mscore.dir/exportxml.cpp.o] Fout 1
make[3]: Map '/usr/local/src/mscore-1.1/build' wordt verlaten
make[2]: *** [mscore/CMakeFiles/mscore.dir/all] Fout 2
make[2]: Map '/usr/local/src/mscore-1.1/build' wordt verlaten
make[1]: *** [all] Fout 2
make[1]: Map '/usr/local/src/mscore-1.1/build' wordt verlaten
make: *** [release] Fout 2

System is Arch linux 3.1.5-1-ARCH #1 SMP PREEMPT, x86_64
gcc (GCC) 4.6.2 20111125 (prerelease)