Send locking assertion backtraces to stderr. Improve the heading on the backtrace.

diff --git a/src/xcb_xlib.c b/src/xcb_xlib.c
index 07d530c..35ad3c3 100644 (file)
--- a/src/xcb_xlib.c
+++ b/src/xcb_xlib.c
@@ -45,10 +45,10 @@ static void xcb_xlib_printbt(void)
        size = backtrace(array, 20);
        strings = backtrace_symbols(array, size);
 
-       printf("Got a backtrace:\n");
+       fprintf(stderr, "Locking assertion failure.  Backtrace:\n");
 
        for (i = 0; i < size; ++i)
-               printf("#%i %s\n", i, strings[i]);
+               fprintf(stderr, "#%i %s\n", i, strings[i]);
 
        free(strings);
 #endif