Second ivl_assert patch

This patch adds a do/while around the conditional

ivl_assert.h

@@ -23,11 +23,13 @@
 # include  <cstdlib>
 
 #define ivl_assert(tok, expression)  \
+      do { \
 	    if (! (expression)) { \
 		  cerr << (tok).get_fileline() << ": assert: " \
 		       << __FILE__ << ":" << __LINE__ \
 		       << ": failed assertion " << #expression << endl; \
 		  abort(); \
-      }
+	    } \
+      } while (0)
 
 #endif