Index: uspace/lib/c/generic/cap.c
===================================================================
--- uspace/lib/c/generic/cap.c	(revision 96b02eb9b2f96f3843b8275c254c43a9cb6c8c88)
+++ uspace/lib/c/generic/cap.c	(revision 6b10dab6510950964fc02ac960103bbaedf76314)
@@ -31,6 +31,6 @@
  */
 /**
- * @file	cap.c
- * @brief	Functions to grant/revoke capabilities to/from a task.
+ * @file  cap.c
+ * @brief Functions to grant/revoke capabilities to/from a task.
  */
 
@@ -38,36 +38,43 @@
 #include <task.h>
 #include <libc.h>
-#include <kernel/syscall/sysarg64.h>
 
 /** Grant capabilities to a task.
  *
- * @param id Destination task ID.
+ * @param id   Destination task ID.
  * @param caps Capabilities to grant.
  *
  * @return Zero on success or a value from @ref errno.h on failure.
+ *
  */
 int cap_grant(task_id_t id, unsigned int caps)
 {
-	sysarg64_t arg;
+#ifdef __32_BITS__
+	sysarg64_t arg = (sysarg64_t) id;
+	return __SYSCALL2(SYS_CAP_GRANT, (sysarg_t) &arg, (sysarg_t) caps);
+#endif
 	
-	arg.value = (unsigned long long) id;
-
-	return __SYSCALL2(SYS_CAP_GRANT, (sysarg_t) &arg, (sysarg_t) caps);
+#ifdef __64_BITS__
+	return __SYSCALL2(SYS_CAP_GRANT, (sysarg_t) id, (sysarg_t) caps);
+#endif
 }
 
 /** Revoke capabilities from a task.
  *
- * @param id Destination task ID.
+ * @param id   Destination task ID.
  * @param caps Capabilities to revoke.
  *
  * @return Zero on success or a value from @ref errno.h on failure.
+ *
  */
 int cap_revoke(task_id_t id, unsigned int caps)
 {
-	sysarg64_t arg;
+#ifdef __32_BITS__
+	sysarg64_t arg = (sysarg64_t) id;
+	return __SYSCALL2(SYS_CAP_REVOKE, (sysarg_t) &arg, (sysarg_t) caps);
+#endif
 	
-	arg.value = (unsigned long long) id;
-
-	return __SYSCALL2(SYS_CAP_REVOKE, (sysarg_t) &arg, (sysarg_t) caps);
+#ifdef __64_BITS__
+	return __SYSCALL2(SYS_CAP_REVOKE, (sysarg_t) id, (sysarg_t) caps);
+#endif
 }
 
Index: uspace/lib/c/generic/ipc.c
===================================================================
--- uspace/lib/c/generic/ipc.c	(revision 96b02eb9b2f96f3843b8275c254c43a9cb6c8c88)
+++ uspace/lib/c/generic/ipc.c	(revision 6b10dab6510950964fc02ac960103bbaedf76314)
@@ -38,5 +38,5 @@
  */
 /** @file
- */ 
+ */
 
 #include <ipc/ipc.h>
@@ -845,16 +845,19 @@
 }
 
-#include <kernel/syscall/sysarg64.h>
 /** Connect to a task specified by id.
+ *
  */
 int ipc_connect_kbox(task_id_t id)
 {
-	sysarg64_t arg;
-
-	arg.value = (unsigned long long) id;
-
+#ifdef __32_BITS__
+	sysarg64_t arg = (sysarg64_t) id;
 	return __SYSCALL1(SYS_IPC_CONNECT_KBOX, (sysarg_t) &arg);
-}
- 
+#endif
+	
+#ifdef __64_BITS__
+	return __SYSCALL1(SYS_IPC_CONNECT_KBOX, (sysarg_t) id);
+#endif
+}
+
 /** @}
  */
Index: uspace/lib/c/include/libc.h
===================================================================
--- uspace/lib/c/include/libc.h	(revision 96b02eb9b2f96f3843b8275c254c43a9cb6c8c88)
+++ uspace/lib/c/include/libc.h	(revision 6b10dab6510950964fc02ac960103bbaedf76314)
@@ -40,4 +40,11 @@
 #include <libarch/syscall.h>
 
+#ifdef __32_BITS__
+
+/** Explicit 64-bit arguments passed to syscalls. */
+typedef uint64_t sysarg64_t;
+
+#endif /* __32_BITS__ */
+
 #define __SYSCALL0(id) \
 	__syscall0(0, 0, 0, 0, 0, 0, id)
@@ -53,5 +60,5 @@
 	__syscall5(p1, p2, p3, p4, p5, 0, id)
 #define __SYSCALL6(id, p1, p2, p3, p4, p5, p6) \
-    __syscall6(p1, p2, p3, p4, p5, p6, id)
+	__syscall6(p1, p2, p3, p4, p5, p6, id)
 
 extern void __main(void *pcb_ptr);