More explicit keywords.

llvm-svn: 40757
diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.h b/llvm/lib/Target/PowerPC/PPCISelLowering.h
index 245fe53..b6b52ef 100644
--- a/llvm/lib/Target/PowerPC/PPCISelLowering.h
+++ b/llvm/lib/Target/PowerPC/PPCISelLowering.h
@@ -186,7 +186,7 @@
     int ReturnAddrIndex;              // FrameIndex for return slot.
     const PPCSubtarget &PPCSubTarget;
   public:
-    PPCTargetLowering(PPCTargetMachine &TM);
+    explicit PPCTargetLowering(PPCTargetMachine &TM);
     
     /// getTargetNodeName() - This method returns the name of a target specific
     /// DAG node.