gprbuild: Move output to build/
diff --git a/default.gpr b/default.gpr
index 96aed41..3d0a261 100644
--- a/default.gpr
+++ b/default.gpr
@@ -2,6 +2,7 @@
    for Languages use ("ada", "c");
    for Main use ("main.c");
    for Source_Dirs use ("src");
+   for Object_Dir use "build";
 
    package Builder is
       for Global_Configuration_Pragmas use "default.adc";