Add glibc2.15-based host toolchain.

Build instructions:
  MYGCCBIN="`pwd`/../x86_64-linux-glibc2.11-4.8/bin"
  CC=$MYGCCBIN/x86_64-linux-gcc \
  CXX=$MYGCCBIN/x86_64-linux-g++ \
  ./build-precise-multilib-toolchain.sh \
  --work-dir=$MYWORKDIR

After build:
* Add symbolic link:
    sysroot/usr/include/stdatomic.h
* Copy from precise (12.04):
    /usr/lib/i386-linux-gnu/libxcb.so.1.1.0
    /usr/lib/i386-linux-gnu/libxcb.so.1 -> libxcb.so.1.1.0
    /usr/lib/x86_64-linux-gnu/libxcb.so.1.1.0
    /usr/lib/x86_64-linux-gnu/libxcb.so.1 -> libxcb.so.1.1.0
  to
    sysroot/usr/lib32/libxcb.so.1.1.0
    sysroot/usr/lib32/libxcb.so.1 -> libxcb.so.1.1.0
    sysroot/usr/lib/libxcb.so.1.1.0
    sysroot/usr/lib/libxcb.so.1 -> libxcb.so.1.1.0

BUG: 17915392
Change-Id: I355e28b922101700719c0cc27f588782f96979d4
3539 files changed