mathfactory.cpp does not compile

[Uwe Stöhr]

On my second PC I am still able to compile LyX. After some months I compiled LyX there now again and 
get this compilation error:

  d:\lyxgit\master\src\mathed\mathfactory.cpp(139): error C4716: 'lyx::`anonymous 
namespace'::isUnicodeSymbolAvailable' : must return a value 
[D:\LyXGit\Master\compile-result\src\mathed\mathed.vcxproj]

regards Uwe