upgrade to c++11

[Frédéric Bron]

Hi,

g++ defaults to the C++ standard of 2003. 2 years ago a new standard
has been published with a log of improvements.
Today the g++ commands in the build process of lilypond do not specify
any standard so that it defaults to c++03.
Could we switch to c++11?
I suspect that a test would be required. Can somebody tell me where I
should add the option -std=c++11 to test this?
For example, can I just replace the following line of aclocal.m4:
CFLAGS=" -pipe $CFLAGS"
by
CFLAGS=" -pipe -std=c++11 $CFLAGS"

Regards,

Frédéric