Add barebones build and ignore rules

Change-Id: Ib8b401d64fde065b824c9d180724de1184cfcf2e
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..1eab063
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+/**/build*/
+/**/subprojects/*/