- Added "Empty" claim type, which is ignored.

Syntax example:   claim_x(I, Empty);

src/compiler.c

@@ -64,6 +64,7 @@ Term TERM_Claim;
 Term CLAIM_Secret;
 Term CLAIM_Nisynch;
 Term CLAIM_Niagree;
+Term CLAIM_Empty;
 
 /*
  * Global stuff
@@ -108,6 +109,7 @@ compilerInit (const System mysys)
   langcons (CLAIM_Secret, "Secret", TERM_Claim);
   langcons (CLAIM_Nisynch, "Nisynch", TERM_Claim);
   langcons (CLAIM_Niagree, "Niagree", TERM_Claim);
+  langcons (CLAIM_Empty, "Empty", TERM_Claim);
 }
 
 //! Make a global constant
@@ -593,6 +595,10 @@ commEvent (int event, Tac tc)
 	    }
 	  break;
 	}
+      if (claim == CLAIM_Empty)
+	{
+	  break;
+	}
 
       /* hmm, no handler yet */