Index: source/Core/ArchSpec.cpp
===================================================================
--- source/Core/ArchSpec.cpp
+++ source/Core/ArchSpec.cpp
@@ -886,6 +886,11 @@
                             break;
                     }
                 }
+                else if (arch_type == eArchTypeELF)
+                {
+                    // Don't set OS for ELF so it can be fulfilled by merging with host or target architecture.
+                    m_triple.setVendor (llvm::Triple::UnknownVendor);
+                }
                 else
                 {
                     m_triple.setVendor (llvm::Triple::UnknownVendor);