Add informational message to help with updation of VNDK abi references.

Test: create reference dump for libjpeg; add exported function to libjpeg;
      m -j libjpeg.vendor, build fails with helpful message.

Test: create reference dump for libjpeg; add exported function to libjpeg;
      m -j libjpeg.vendor dist DIST_DIR=dist, build fails with helpful message.

Change-Id: Iae25374fe937a0cbe8a8ddf9e23c3bc1f62bbb2a
diff --git a/cc/builder.go b/cc/builder.go
index 53ef69c..a88df88 100644
--- a/cc/builder.go
+++ b/cc/builder.go
@@ -203,9 +203,11 @@
 
 			commandStr := "($sAbiDiffer $allowFlags -lib $libName -arch $arch -check-all-apis -o ${out} -new $in -old $referenceDump)"
 			distAbiDiffDir := android.PathForDist(ctx, "abidiffs")
+			commandStr += "|| (echo ' ---- Please update abi references by running platform/development/vndk/tools/header-checker/utils/create_reference_dumps.py -l ${libName} ----'"
 			if distAbiDiffDir.Valid() {
-				commandStr += "  || (mkdir -p " + distAbiDiffDir.String() + " && cp ${out} " + distAbiDiffDir.String() + " && exit 1)"
+				commandStr += ")  && (mkdir -p " + distAbiDiffDir.String() + " && cp ${out} " + distAbiDiffDir.String()
 			}
+			commandStr += " && exit 1)"
 			return blueprint.RuleParams{
 				Command:     commandStr,
 				CommandDeps: []string{"$sAbiDiffer"},
@@ -740,7 +742,7 @@
 		Implicit:    referenceDump,
 		Args: map[string]string{
 			"referenceDump": referenceDump.String(),
-			"libName":       baseName,
+			"libName":       baseName[0:(len(baseName) - len(filepath.Ext(baseName)))],
 			"arch":          ctx.Arch().ArchType.Name,
 			"allowFlags":    strings.Join(localAbiCheckAllowFlags, " "),
 		},