Work around lack of %zd printf format specifier in MSVC libs.

llvm-svn: 233569
diff --git a/lldb/tools/driver/Driver.cpp b/lldb/tools/driver/Driver.cpp
index 928c75e..3df6bb2 100644
--- a/lldb/tools/driver/Driver.cpp
+++ b/lldb/tools/driver/Driver.cpp
@@ -882,9 +882,9 @@
         ssize_t nrwr = write(fds[WRITE], commands_data, commands_size);
         if (nrwr < 0)
         {
-            fprintf(stderr, "error: write(%i, %p, %zd) failed (errno = %i) "
+            fprintf(stderr, "error: write(%i, %p, %" PRIu64 ") failed (errno = %i) "
                             "when trying to open LLDB commands pipe\n",
-                    fds[WRITE], commands_data, commands_size, errno);
+                    fds[WRITE], commands_data, static_cast<uint64_t>(commands_size), errno);
             success = false;
         }
         else if (static_cast<size_t>(nrwr) == commands_size)