From b3af872f3c9e4547ea27d914a463bb5e63f6fd07 Mon Sep 17 00:00:00 2001
From: Simon Tatham <anakin@pobox.com>
Date: Tue, 12 Jan 2010 23:32:22 +0000
Subject: [PATCH] Patch from James H: make the Windows debugging output
 conditional on an enabling environment variable.

[originally from svn r8834]
---
 windows.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/windows.c b/windows.c
index d2044cc..7bdb5e2 100644
--- a/windows.c
+++ b/windows.c
@@ -154,11 +154,17 @@ void debug_printf(char *fmt, ...)
 {
     char buf[4096];
     va_list ap;
+    static int debugging = -1;
 
-    va_start(ap, fmt);
-    _vsnprintf(buf, 4095, fmt, ap);
-    dputs(buf);
-    va_end(ap);
+    if (debugging == -1)
+        debugging = getenv("DEBUG_PUZZLES") ? 1 : 0;
+
+    if (debugging) {
+        va_start(ap, fmt);
+        _vsnprintf(buf, 4095, fmt, ap);
+	dputs(buf);
+        va_end(ap);
+    }
 }
 #endif