1 files changed, 2 insertions, 1 deletions
diff --git a/io.c b/io.c
index d59bde93cf..eeb4d66063 100644
--- a/io.c
+++ b/io.c
@@ -138,7 +138,8 @@ off_t __syscall(quad_t number, ...);
 #if defined(_WIN32)
 #  define RUBY_PIPE_NONBLOCK_DEFAULT    (0)
 #elif defined(O_NONBLOCK)
-#  define RUBY_PIPE_NONBLOCK_DEFAULT    (O_NONBLOCK)
+  /* disabled for [Bug #15356] (Rack::Deflater + rails) failure: */
+#  define RUBY_PIPE_NONBLOCK_DEFAULT    (0)
 #else /* any platforms where O_NONBLOCK does not exist? */
 #  define RUBY_PIPE_NONBLOCK_DEFAULT    (0)
 #endif