[vala] Added error when not exporting any namespaces for GIR

[Jesse van den Kieboom <jessevdk src gnome org>]

commit ebb9d4435279bbb333adc77bbd41dc8d0fd9929a
Author: Jesse van den Kieboom <jesse vandenkieboom epfl ch>
Date:   Tue Feb 7 11:22:35 2012 +0100

    Added error when not exporting any namespaces for GIR
    
    https://bugzilla.gnome.org/show_bug.cgi?id=669551

 codegen/valagirwriter.vala |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/codegen/valagirwriter.vala b/codegen/valagirwriter.vala
index fc2c6bf..eff9748 100644
--- a/codegen/valagirwriter.vala
+++ b/codegen/valagirwriter.vala
@@ -188,6 +188,10 @@ public class Vala.GIRWriter : CodeVisitor {
 			ns.source_reference.file.gir_namespace = gir_namespace;
 			ns.source_reference.file.gir_version = gir_version;
 		}
+
+		if (our_namespaces.size == 0) {
+			Report.error (null, "No suitable namespace found to export for GIR");
+		}
 	}
 
 	private void write_doc (string? comment) {