libc/glibc: print name of skipped addon

When trying to extract an already present (aka bundled) addon,
print the name of that addon, for clarity, and to help analyse
the build.log post-mortem.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

# windows config options

## depends on ARCH_x86

##

## select WINDOWS

##

## help Build a toolchain targeting systems running Windows as host