C++11 warnings result in build failure.

[edsu]

When building on Ubuntu I'm seeing warnings like this that ultimately result in a build failure:

In file included from /code/libmei-3.1.0/src/meiattribute.cpp:2:0:
/code/libmei-3.1.0/src/meielement.h:181:44: warning: dynamic exception specifications are deprecated in C++11 [-Wdeprecated]
         void setDocument(MeiDocument *doc) throw (DocumentRootNotSetException);

Normally warnings are not considered errors, but the compiler is being asked to make them errorrs. When I remove those lines the build succeeds.

[mprevot]

For non developers, adding add_definitions( -w ) to silent warnings is also a good thing to do.