newlib contains very little code under [L]GPL. No [L]GPL code is supposed to be in any configuration unless it is in the OS specific code. For GNU/Linux, this source is under the libc/sys/linux subdirectory.
If Google had chosen newlib, there would have been less work to get it clean for Android than putting together a new library.
FWIW newlib is used by Cygwin and RTEMS along with bare metal users of GNU tools. It supports a variety of architectures. Newlib is an old project with a community around it.