Index: trunk/data/validator/deprecated.mapcss
===================================================================
--- trunk/data/validator/deprecated.mapcss	(revision 13217)
+++ trunk/data/validator/deprecated.mapcss	(revision 13218)
@@ -1164,2 +1164,10 @@
   group: tr("deprecated tagging");
 }
+
+way[building=y],
+way[building=1] {
+  throwError: tr("{0}", "{0.tag}");
+  suggestAlternative: "building=yes";
+  group: tr("misspelled value");
+  fixAdd: "building=yes";
+}
Index: trunk/styles/standard/elemstyles.mapcss
===================================================================
--- trunk/styles/standard/elemstyles.mapcss	(revision 13217)
+++ trunk/styles/standard/elemstyles.mapcss	(revision 13218)
@@ -297,5 +297,5 @@
     dashes: 2,2;
 }
-area[building][!building?!] {
+area[building][!building?!][building!=y][building!=1] {
     fill-color: building#cb9999;
 }