uClibc++: Fix three bugs

uClibc++: Fix three bugs

The first allows usage of several functions in the std namespace, which
broke compilation of gddrescue specifically with uClibc-ng and uClibc++.

The second allows usage of long long with normal C++11, which is part of
the standard. Before, std=gnu++11 needed to be passsed to work around it.

As a result of the second patch, the pedantic patch can safely be removed.

Both patches are upstream backports.

Added -std=c++11 to CFLAGS to guarentee proper inclusion of long long.

Added another patch that fixes a typo with the long long support. Sent to
upstream.

Fixed up license information according to SPDX.

Small cleanups for consistency.

Signed-off-by: Rosen Penev <rosenp@gmail.com>