Make org.eclipse.debug optional dependency
diff --git a/plugins/org.eclipse.m2m.qvt.oml.common/META-INF/MANIFEST.MF b/plugins/org.eclipse.m2m.qvt.oml.common/META-INF/MANIFEST.MF
index eb28e24..315266f 100644
--- a/plugins/org.eclipse.m2m.qvt.oml.common/META-INF/MANIFEST.MF
+++ b/plugins/org.eclipse.m2m.qvt.oml.common/META-INF/MANIFEST.MF
@@ -48,7 +48,7 @@
 Require-Bundle: org.eclipse.core.runtime;bundle-version="[3.4.0,4.0.0)",
  org.eclipse.core.resources;bundle-version="[3.4.0,4.0.0)",
  org.eclipse.core.filesystem;bundle-version="[1.2.0,2.0.0)";visibility:=reexport,
- org.eclipse.debug.core;bundle-version="[3.4.0,4.0.0)",
+ org.eclipse.debug.core;bundle-version="[3.4.0,4.0.0)";resolution:=optional,
  org.eclipse.emf.ecore;bundle-version="[2.5.0,3.0.0)",
  org.eclipse.m2m.qvt.oml.emf.util;bundle-version="[2.0.0,3.0.0)"
 Bundle-ActivationPolicy: lazy