Bug#789481: musescore: FTBFS on architectures where char is not signed

[Andreas Beckmann]

Source: musescore
Version: 2.0.1+dfsg-1
Severity: serious

Many architectures FTBFS:
https://buildd.debian.org/status/package.php?p=musescore&suite=unstable

from the arm64 log:

[ 10%] Building CXX object mstyle/CMakeFiles/mstyle.dir/menubarengine.cpp.o
In file included from <command-line>:0:0:
/usr/include/stdc-predef.h:59:1: warning: /«BUILDDIR»/musescore-2.0.1+dfsg/build.release/all.h.gch: not used because `_FORTIFY_SOURCE' is defined [-Winvalid-pch]
 #endif
 ^
In file included from /«BUILDDIR»/musescore-2.0.1+dfsg/libmscore/stafftype.h:16:0,
                 from /«BUILDDIR»/musescore-2.0.1+dfsg/libmscore/xml.h:17,
                 from /«BUILDDIR»/musescore-2.0.1+dfsg/fluid/sfont.cpp:30:
/«BUILDDIR»/musescore-2.0.1+dfsg/libmscore/element.h:48:18: error: enumerator value -1 is outside the range of underlying type 'char'
       NO_GRIP = -1,
                  ^
In file included from /«BUILDDIR»/musescore-2.0.1+dfsg/libmscore/note.h:24:0,
                 from /«BUILDDIR»/musescore-2.0.1+dfsg/libmscore/durationtype.h:17,
                 from /«BUILDDIR»/musescore-2.0.1+dfsg/libmscore/stafftype.h:19,
                 from /«BUILDDIR»/musescore-2.0.1+dfsg/libmscore/xml.h:17,
                 from /«BUILDDIR»/musescore-2.0.1+dfsg/fluid/sfont.cpp:30:
/«BUILDDIR»/musescore-2.0.1+dfsg/libmscore/pitchspelling.h:56:42: error: enumerator value -1 is outside the range of underlying type 'char'
 enum class NoteCaseType : char { AUTO = -1, CAPITAL = 0, LOWER, UPPER };
                                          ^

There is also another problem on x86:

musescore-soundfont-gm/amd64 unsatisfiable Depends: timgm6mb-soundfont
musescore-soundfont-gm/i386 unsatisfiable Depends: timgm6mb-soundfont


Andreas