Merge changes I65f8bbbc,Iaa65e2d1,Ifa0139c9,Ic39d2a2b,I78cf0a23

* changes:
  backport fix for PR65735
  backport patch to fix PR65177
  backport patch to fix PR65048
  backport patch for PR 64878: do not jump thread across more than one back-edge
  port revision 219584 from linaro/gcc-4_9-branch
tree: 111942606d6f12c7aa3dc294d0040d9a3c134ae2
  1. gcc-4.8/
  2. gcc-4.9/
  3. build-gcc.sh
  4. build.py