Restrict to linux,gtk,x86

Change-Id: I5e38f3591311cecdb40f096694b34d302c0ba21b
diff --git a/releng/org.eclipse.graphiti.releng/build.mspec b/releng/org.eclipse.graphiti.releng/build.mspec
index 40222ca..a550e82 100644
--- a/releng/org.eclipse.graphiti.releng/build.mspec
+++ b/releng/org.eclipse.graphiti.releng/build.mspec
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>

 <mspec:mspec xmlns:mspec="http://www.eclipse.org/buckminster/MetaData-1.0" installLocation="" materializer="p2" name="build.mspec" url="build.cquery">

-  <mspec:property key="target.os" value="aix"/>

+  <mspec:property key="target.os" value="linux"/>

   <mspec:property key="target.ws" value="gtk"/>

-  <mspec:property key="target.arch" value="ppc"/>

+  <mspec:property key="target.arch" value="x86"/>

   <mspec:mspecNode materializer="workspace" filter="(buckminster.source=true)"/>

 </mspec:mspec>