Define truncate64, ftruncate64, and getdents64 decoders unconditionally

These decoders are referenced by most architectures, there were no
undefined references so far because _LFS64_LARGEFILE appears to be
always defined by glibc when _GNU_SOURCE is defined.

* file.c (sys_truncate64, sys_ftruncate64, sys_getdents64): Define
unconditionally.
diff --git a/file.c b/file.c
index 6feb947..98dc713 100644
--- a/file.c
+++ b/file.c
@@ -632,7 +632,6 @@
 	return 0;
 }
 
-#if _LFS64_LARGEFILE
 int
 sys_truncate64(struct tcb *tcp)
 {
@@ -642,7 +641,6 @@
 	}
 	return 0;
 }
-#endif
 
 int
 sys_ftruncate(struct tcb *tcp)
@@ -654,7 +652,6 @@
 	return 0;
 }
 
-#if _LFS64_LARGEFILE
 int
 sys_ftruncate64(struct tcb *tcp)
 {
@@ -664,7 +661,6 @@
 	}
 	return 0;
 }
-#endif
 
 /* several stats */
 
@@ -2310,7 +2306,6 @@
 	return 0;
 }
 
-#if _LFS64_LARGEFILE
 int
 sys_getdents64(struct tcb *tcp)
 {
@@ -2372,7 +2367,6 @@
 	free(buf);
 	return 0;
 }
-#endif
 
 int
 sys_getcwd(struct tcb *tcp)