CFLAGS and CXXFLAGS must not be set during the building of cross-tools.

To disable CFLAGS and CXXFLAGS use the following commands:

unset CFLAGS
unset CXXFLAGS

Now add these to ~/.bashrc, just in case you have to exit and restart building later:

echo unset CFLAGS >> ~/.bashrc
echo unset CXXFLAGS >> ~/.bashrc