diff --git a/src/configure b/src/configure
index 075964c00..7ca891548 100755
--- a/src/configure
+++ b/src/configure
@@ -5250,6 +5250,7 @@ else
 		                       res1 = (i == (int)arg);
                              else
 		                       res2 = (i == (int)arg);
+		             return NULL;
                            }
 	                       __thread int i;
                            int main () {
@@ -5378,7 +5379,7 @@ else
                                exit(1);
                              }
                              done = 1;
-	                         return j;
+			     return (void *) j;
                            }
 
                            int main( int argc, char ** argv ) {
diff --git a/src/configure.in b/src/configure.in
index 7d95ae1a4..f9b494036 100644
--- a/src/configure.in
+++ b/src/configure.in
@@ -721,6 +721,7 @@ AC_ARG_WITH(tls,
 		                       res1 = (i == (int)arg);
                              else
 		                       res2 = (i == (int)arg);
+		             return NULL;
                            }
 	                       __thread int i;
                            int main () {
@@ -812,7 +813,7 @@ AC_ARG_WITH(virtualtimer,
                                exit(1);
                              }        
                              done = 1;
-	                         return j;
+			     return (void *) j;
                            } 
   
                            int main( int argc, char ** argv ) {