Add a -fuse-init-array option to cc1 and map to the UseInitArray target
option. On the driver, check if we are using libraries from gcc 4.7 or newer
and if so pass -fuse-init-array to the frontend.
The crtbegin*.o files in gcc 4.7 no longer call the constructors listed in
.ctors, so we have to use .init_array.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@158694 91177308-0d34-0410-b5e6-96231b3b80d8
10 files changed