MFC r327930:
Pull in r314499 from upstream clang trunk (by Daniel Marjamäki):
[Sema] Suppress warnings for C's zero initializer Patch by S. Gilles! Differential Revision: https://reviews.llvm.org/D28148
Pull in r314838 from upstream clang trunk (by Richard Smith):
Suppress -Wmissing-braces warning when aggregate-initializing a struct with a single field that is itself an aggregate. In C++, such initialization of std::array<T, N> types is guaranteed to work by the standard, is completely idiomatic, and the "suggested" alternative from Clang was technically invalid.
Together, these suppress unneeded "suggest braces around initialization
of subobject" warnings for C++11 initializer lists.