Don't drop alignment info on local common symbols.

- On COFF the .lcomm directive has an alignment argument.
- On ELF we fall back to .local + .comm

Based on a patch by NAKAMURA Takumi.

Fixes PR9337, PR9483 and PR10128.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@138976 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/MC/MCMachOStreamer.cpp b/lib/MC/MCMachOStreamer.cpp
index 844793b..aa35815 100644
--- a/lib/MC/MCMachOStreamer.cpp
+++ b/lib/MC/MCMachOStreamer.cpp
@@ -67,7 +67,8 @@
   virtual void EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) {
     assert(0 && "macho doesn't support this directive");
   }
-  virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size) {
+  virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
+                                     unsigned ByteAlignment) {
     assert(0 && "macho doesn't support this directive");
   }
   virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol = 0,