x32: fix struct dirent decoding

* kernel_types.h: New file.
* Makefile.am (strace_SOURCES): Add it.
* configure.ac (AC_CHECK_TYPES): Check for __kernel_long_t
and __kernel_ulong_t in <asm/posix_types.h>.
* dirent.c: Stop including <dirent.h>.
(kernel_dirent): Remove.
Include "kernel_types.h".
(print_old_dirent, SYS_FUNC(getdents)): Print variables
of kernel_ulong_t type using %Lu format.
* syscall.c (kernel_long_t, kernel_ulong_t): Remove.
Include "kernel_types.h".
* tests/getdents.c (kernel_dirent): Remove.
Include "kernel_types.h".
(print_dirent): Print variables of kernel_ulong_t type using %Lu format.
diff --git a/syscall.c b/syscall.c
index bff00c9..d603c5c 100644
--- a/syscall.c
+++ b/syscall.c
@@ -1156,22 +1156,7 @@
 	tcp->u_error = saved_u_error;
 }
 
-/*
- * Cannot rely on __kernel_[u]long_t being defined,
- * it is quite a recent feature of <asm/posix_types.h>.
- */
-#ifdef __kernel_long_t
-typedef __kernel_long_t kernel_long_t;
-typedef __kernel_ulong_t kernel_ulong_t;
-#else
-# ifdef X32
-typedef long long kernel_long_t;
-typedef unsigned long long kernel_ulong_t;
-# else
-typedef long kernel_long_t;
-typedef unsigned long kernel_ulong_t;
-# endif
-#endif
+#include "kernel_types.h"
 
 /*
  * Check the syscall return value register value for whether it is