Better handling for tabs with message bubbles.

llvm-svn: 49001
diff --git a/clang/Driver/HTMLDiagnostics.cpp b/clang/Driver/HTMLDiagnostics.cpp
index df2bb06..7f6a369 100644
--- a/clang/Driver/HTMLDiagnostics.cpp
+++ b/clang/Driver/HTMLDiagnostics.cpp
@@ -205,7 +205,7 @@
   unsigned PosNo = 0;
   
   for (const char* c = LineStart; c != TokLogicalPtr; ++c)
-    PosNo += *c == '\t' ? 8 : 1;
+    PosNo += *c == '\t' ? 4 : 1;
   
   // Create the html for the message.