Ensure we have the off64_t variant of every function that takes an off_t.

Change-Id: Ib2eee0cf13162be3b62559b84e90c6dcf5aab1c3
diff --git a/libc/arch-mips/syscalls/truncate64.S b/libc/arch-mips/syscalls/truncate64.S
new file mode 100644
index 0000000..57f0b5f
--- /dev/null
+++ b/libc/arch-mips/syscalls/truncate64.S
@@ -0,0 +1,22 @@
+/* autogenerated by gensyscalls.py */
+#include <asm/unistd.h>
+    .text
+    .globl truncate64
+    .align 4
+    .ent truncate64
+
+truncate64:
+    .set noreorder
+    .cpload $t9
+    li $v0, __NR_truncate64
+    syscall
+    bnez $a3, 1f
+    move $a0, $v0
+    j $ra
+    nop
+1:
+    la $t9,__set_errno
+    j $t9
+    nop
+    .set reorder
+    .end truncate64