Allow swtmenubar module to be buildable on Windows.

Change-Id: Ia20b8dea44f79df77ba0cb0479b99af990dc5b7b
diff --git a/core/main.mk b/core/main.mk
index 858819b..c23112b 100644
--- a/core/main.mk
+++ b/core/main.mk
@@ -429,6 +429,7 @@
 	sdk/ninepatch \
 	sdk/sdkstats \
 	sdk/sdkmanager \
+	sdk/swtmenubar \
 	development/apps \
 	development/tools/mkstubs \
 	packages