Switch Linux toolchain from glibc2.11 to glibc2.15

This change gets Windows gcc building again. (ab/aosp-gcc)

Bug: b/73539603
Test: ./toolchain/gcc/build.py  --toolchain arm-linux-androideabi --host linux
Test: ./toolchain/gcc/build.py  --toolchain arm-linux-androideabi --host windows
Test: ./toolchain/gcc/build.py  --toolchain arm-linux-androideabi --host windows64
1 file changed
tree: 81ab58e755a67bb3ef9fb210a5649ee8e23db6ae
  1. default.xml