Allow to build 10.6 binaries on Darwin x86_64 (the following binaries were actually built on such).
Roll the newer (r4383) TSan binaries for Mac OS 10.6 which reports less errors than the previous one (r2939) locally.
Because we didn't track the TSan versions before, I've set them to unknown for all the platforms.

Review URL:

git-svn-id: 4ff67af0-8c30-449e-8e8b-ad334ec8d88c
diff --git a/ b/
index d00171d..a4c5a33 100755
--- a/
+++ b/
@@ -70,7 +70,7 @@
   # }}}
 TSAN_DIR="$VG_SRC_DIR/tsan" # Directory to checkout TSan sources
 rm -rf "$TSAN_DIR"
 svn co -r "$TSAN_REV" "$TSAN_DIR"
diff --git a/ b/
index 9607331..7a69f56 100755
--- a/
+++ b/
@@ -175,6 +175,9 @@
       if system_is_lion
         build_valgrind "mac_10.7"
+      elif system_is_snow_leopard
+      then
+        build_valgrind "mac_10.6" "--build=amd64-darwin"
         echo "You have Darwin kernel different from 11.X.X" >&2
         echo "Please, don't put the resulting binaries into Chromium SVN" >&2