Include pthread.h in butler.h for mingw build

Jack2 on windows doesn't include pthread headers so it is necessary
to include them explicitly.

diff --git a/libs/ardour/ardour/butler.h b/libs/ardour/ardour/butler.h
index 81159f7d3c65b7b1980e760e1982f8da18a5e8f9..97020bed66e710308b935cb00df1aae0a1ddb65f 100644 (file)
--- a/libs/ardour/ardour/butler.h
+++ b/libs/ardour/ardour/butler.h
@@ -20,6 +20,8 @@
 #ifndef __ardour_butler_h__
 #define __ardour_butler_h__
 
+#include <pthread.h>
+
 #include <glibmm/threads.h>
 
 #ifdef WIN32