- Copy stable/10@285827 to releng/10.2 in preparation for 10.2-RC1
builds.
- Update newvers.sh to reflect RC1.
- Update __FreeBSD_version to reflect 10.2.
- Update default pkg(8) configuration to use the quarterly branch.[1]

Discussed with: re, portmgr [1]
Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

MFC r271931:

Add a few missing llvm/clang patches, update the other ones to be able
to apply with the same patch options onto a fresh upstream llvm/clang
3.4.1 checkout, and use approximately the same header tempate for them.

MFC Clang debuginfo crash fix

r271432: Merge upstream Clang rev 205331 debuginfo crash fix:

Debug info: fix a crash when emitting IndirectFieldDecls, which were
previously not handled at all.
rdar://problem/16348575

r271433: Add clang patch corresponding to r271432

Approved by: re
Sponsored by: DARPA, AFRL

Add clang patch corresponding to r271432