diff --git a/libs/backends/portaudio/wscript b/libs/backends/portaudio/wscript
index 4f3395f93e..0d679a1563 100644
--- a/libs/backends/portaudio/wscript
+++ b/libs/backends/portaudio/wscript
@@ -36,6 +36,5 @@ def build(bld):
     obj.install_path  = os.path.join(bld.env['LIBDIR'], 'backends')
     obj.defines = ['PACKAGE="' + I18N_PACKAGE + '"',
                    'ARDOURBACKEND_DLL_EXPORTS',
-                   'USE_MMCSS_THREAD_PRIORITIES',
-                   'USE_BLOCKING_API'
+                   'USE_MMCSS_THREAD_PRIORITIES'
                   ]