meson: Prepare for subprojects

Google-Bug-Id: 179721407
Change-Id: I517dcb47d7c73fa4f3c7fcc25146b77de50d69b8
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/hello.c b/hello.c
new file mode 100644
index 0000000..067ca5d
--- /dev/null
+++ b/hello.c
@@ -0,0 +1,3 @@
+// Dummy executable needed to work around coverage
+int main()
+{}