Finishing touch for the std::error_code transition.

While std::error_code itself seems to work OK in all platforms, there
are few annoying differences with regards to the std::errc enumeration.

This patch adds a simple llvm enumeration, which will hopefully avoid build
breakages in other platforms and surprises as we get more uses of
std::error_code.

llvm-svn: 210920
diff --git a/llvm/tools/llvm-symbolizer/LLVMSymbolize.cpp b/llvm/tools/llvm-symbolizer/LLVMSymbolize.cpp
index c6bd4e7..dd9ffc1 100644
--- a/llvm/tools/llvm-symbolizer/LLVMSymbolize.cpp
+++ b/llvm/tools/llvm-symbolizer/LLVMSymbolize.cpp
@@ -19,6 +19,7 @@
 #include "llvm/Support/Casting.h"
 #include "llvm/Support/Compression.h"
 #include "llvm/Support/DataExtractor.h"
+#include "llvm/Support/Errc.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Path.h"
@@ -311,7 +312,7 @@
           getDarwinDWARFResourceForPath(Path);
       BinaryOrErr = createBinary(ResourcePath);
       std::error_code EC = BinaryOrErr.getError();
-      if (EC != std::errc::no_such_file_or_directory && !error(EC)) {
+      if (EC != errc::no_such_file_or_directory && !error(EC)) {
         DbgBin = BinaryOrErr.get();
         ParsedBinariesAndObjects.push_back(std::unique_ptr<Binary>(DbgBin));
       }