Convert two char* that are only ever used as booleans to bool.

llvm-svn: 196168
diff --git a/llvm/lib/MC/MCAsmInfo.cpp b/llvm/lib/MC/MCAsmInfo.cpp
index a2ff92f..53c28c2 100644
--- a/llvm/lib/MC/MCAsmInfo.cpp
+++ b/llvm/lib/MC/MCAsmInfo.cpp
@@ -76,8 +76,8 @@
   HasIdentDirective = false;
   HasNoDeadStrip = false;
   WeakRefDirective = 0;
-  WeakDefDirective = 0;
-  LinkOnceDirective = 0;
+  HasWeakDefDirective = false;
+  HasLinkOnceDirective = false;
   HiddenVisibilityAttr = MCSA_Hidden;
   HiddenDeclarationVisibilityAttr = MCSA_Hidden;
   ProtectedVisibilityAttr = MCSA_Protected;