Fixes PR18985
Patch by Vassil Vassilev!
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@231789
91177308-0d34-0410-b5e6-
96231b3b80d8
Use ``__has_feature(c_thread_local)`` or ``__has_extension(c_thread_local)``
to determine if support for ``_Thread_local`` variables is enabled.
+Modules
+-------
+
+Use ``__has_feature(modules)`` to determine if Modules have been enabled.
+For example, compiling code with ``-fmodules`` enables the use of Modules.
+
+More information could be found `here <http://clang.llvm.org/docs/Modules.html>`_.
+
Checks for Type Trait Primitives
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