From 90845974ea26829aa167a9170ff87008eb41d688 Mon Sep 17 00:00:00 2001
From: Tim Moore <timoore33@gmail.com>
Date: Mon, 23 Apr 2018 23:52:18 +0200
Subject: [PATCH] nasal/lib.c: Make copy of va_list for each traversal

It's not portable to traverse a va_list more than once.
---
 simgear/nasal/lib.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/simgear/nasal/lib.c b/simgear/nasal/lib.c
index 796c3ca3..528803b5 100644
--- a/simgear/nasal/lib.c
+++ b/simgear/nasal/lib.c
@@ -302,15 +302,18 @@ static char* dosprintf(char* f, ...)
     char* buf;
     va_list va;
     int olen, len = 16;
+    va_start(va, f);
     while(1) {
         buf = naAlloc(len);
-        va_start(va, f);
-        olen = vsnprintf(buf, len, f, va);
+        va_list vaCopy;
+        va_copy(vaCopy, va);
+        olen = vsnprintf(buf, len, f, vaCopy);
         if(olen >= 0 && olen < len) {
             va_end(va);
+            va_end(vaCopy);
             return buf;
         }
-        va_end(va);
+        va_end(vaCopy);
         naFree(buf);
         len *= 2;
     }