/usr/lib/arm-none-eabi/newlib/armv7-m/libg_nano.a is in libnewlib-arm-none-eabi 2.1.0+git20140818.1a8323b-2.
This file is owned by root:root, with mode 0o644.
It is a symlink to /usr/lib/arm-none-eabi/newlib/armv7-m/./usr/lib/arm-none-eabi/newlib/armv7-m/libc_nano.a