Store OSABI in Config.

This allows us to set a value for it based on -m.

llvm-svn: 285294
diff --git a/lld/ELF/InputFiles.cpp b/lld/ELF/InputFiles.cpp
index b0c177f..34e55ef 100644
--- a/lld/ELF/InputFiles.cpp
+++ b/lld/ELF/InputFiles.cpp
@@ -106,6 +106,7 @@
     : InputFile(K, MB), ELFObj(createELFObj<ELFT>(MB)) {
   EKind = getELFKind<ELFT>();
   EMachine = ELFObj.getHeader()->e_machine;
+  OSABI = ELFObj.getHeader()->e_ident[llvm::ELF::EI_OSABI];
 }
 
 template <class ELFT>