[gnome-builder] tests: add main func to project1 test file

[Christian Hergert <chergert src gnome org>]

commit 1352aeca22aceb8f7a595b4d71c7efd75a22ae21
Author: Christian Hergert <chergert redhat com>
Date:   Wed Dec 21 15:20:40 2016 -0800

    tests: add main func to project1 test file

 tests/data/project1/project1.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/tests/data/project1/project1.c b/tests/data/project1/project1.c
index e69de29..e356ea5 100644
--- a/tests/data/project1/project1.c
+++ b/tests/data/project1/project1.c
@@ -0,0 +1 @@
+int main (int argc, char **argv) { return 0; }