Try to fix the MSVC build

There's some kind of issue with using "constexpr unsigned" in an
anonymous namespace.

http://lab.llvm.org:8011/builders/clang-x64-ninja-win7/builds/13395

llvm-svn: 273770
diff --git a/llvm/tools/llvm-cov/SourceCoverageViewText.cpp b/llvm/tools/llvm-cov/SourceCoverageViewText.cpp
index a7cb507..50c8760 100644
--- a/llvm/tools/llvm-cov/SourceCoverageViewText.cpp
+++ b/llvm/tools/llvm-cov/SourceCoverageViewText.cpp
@@ -19,8 +19,8 @@
 
 namespace {
 
-constexpr unsigned LineCoverageColumnWidth = 7;
-constexpr unsigned LineNumberColumnWidth = 5;
+static const unsigned LineCoverageColumnWidth = 7;
+static const unsigned LineNumberColumnWidth = 5;
 
 /// \brief Get the width of the leading columns.
 unsigned getCombinedColumnWidth(const CoverageViewOptions &Opts) {