[Sanitizers] Fix internal_ftruncate() to work on FreeBSD

[kutuzov.viktor.84]

Summary

off_t is 64 bits wide on FreeBSD regardless of the target width.

[samsonov]

LGTM

compiler-rt/trunk/lib/sanitizer_common/sanitizer_linux.cc

uptr internal_write(fd_t fd, const void *buf, uptr count) {
   sptr res;
   HANDLE_EINTR(res, (sptr)internal_syscall(SYSCALL(write), fd, (uptr)buf,
                count));
   return res;
 }
 
 uptr internal_ftruncate(fd_t fd, uptr size) {
   sptr res;
-  HANDLE_EINTR(res, (sptr)internal_syscall(SYSCALL(ftruncate), fd, size));
+  HANDLE_EINTR(res, (sptr)internal_syscall(SYSCALL(ftruncate), fd,
+               (OFF_T)size));
   return res;
 }
 
 #if !SANITIZER_LINUX_USES_64BIT_SYSCALLS && !SANITIZER_FREEBSD
 static void stat64_to_stat(struct stat64 *in, struct stat *out) {
   internal_memset(out, 0, sizeof(*out));
   out->st_dev = in->st_dev;
   out->st_ino = in->st_ino;