Add missing include (for r205050)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205053 91177308-0d34-0410-b5e6-96231b3b80d8

tools/llvm-mc/llvm-mc.cpp

@@ -26,6 +26,7 @@
 #include "llvm/MC/MCSubtargetInfo.h"
 #include "llvm/MC/MCTargetAsmParser.h"
 #include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Compression.h"
 #include "llvm/Support/FileUtilities.h"
 #include "llvm/Support/FormattedStream.h"
 #include "llvm/Support/Host.h"