Summary:
This avoids a -Wignored-attribute warning on the code pattern Microsoft
recommends for integral const static data members defined in headers
here:
https://docs.microsoft.com/en-us/cpp/build/reference/microsoft-extensions-to-c-and-cpp?view=vs-2019
The attribute is redundant, but it is necessary when compiling in C++14
modes with /Za, which disables MSVC's extension that treats such
variables as implicitly inline.
Fixes PR43270
Reviewers: epastor, thakis, hans
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D67426
llvm-svn: 371749