Change Target & Process so they can really be initialized with an invalid architecture.

Arrange that this then gets properly set on attach, or when a "file" is set.
Add a completer for "process attach -n".

Caveats: there isn't currently a way to handle multiple processes with the same name.  That
will have to wait on a way to pass annotations along with the completion strings.

llvm-svn: 110624

lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp

@@ -145,6 +145,13 @@ ObjectFileELF::~ObjectFileELF()
 {
 }
 
+bool
+ObjectFileELF::IsExecutable() const
+{
+    // FIXME: How is this marked in ELF?
+    return false;
+}
+
 ByteOrder
 ObjectFileELF::GetByteOrder() const
 {