Index: uspace/lib/c/generic/async.c
===================================================================
--- uspace/lib/c/generic/async.c	(revision 46d4d9f449e7933280b1877c70448602ec0ab0ae)
+++ uspace/lib/c/generic/async.c	(revision a4b92fb02227d80cddeca1fc5b42d4cacb2f93ef)
@@ -536,5 +536,5 @@
 		if (callid)
 			ipc_answer_0(callid, ENOMEM);
-		return NULL;
+		return (uintptr_t) NULL;
 	}
 	
@@ -556,5 +556,5 @@
 		if (callid)
 			ipc_answer_0(callid, ENOMEM);
-		return NULL;
+		return (uintptr_t) NULL;
 	}
 	
Index: uspace/lib/c/generic/io/klog.c
===================================================================
--- uspace/lib/c/generic/io/klog.c	(revision 46d4d9f449e7933280b1877c70448602ec0ab0ae)
+++ uspace/lib/c/generic/io/klog.c	(revision a4b92fb02227d80cddeca1fc5b42d4cacb2f93ef)
@@ -52,5 +52,5 @@
 void klog_update(void)
 {
-	(void) __SYSCALL3(SYS_KLOG, 1, NULL, 0);
+	(void) __SYSCALL3(SYS_KLOG, 1, (uintptr_t) NULL, 0);
 }