Try to fix compilation on cygwin

diff --git a/src/support/trivstring.cpp b/src/support/trivstring.cpp
index fa714e9402fb4de220243cabbb64c7253099c3a1..6fda216674ebb33c1738c26540ad389cf774b370 100644 (file)
--- a/src/support/trivstring.cpp
+++ b/src/support/trivstring.cpp
@@ -15,6 +15,7 @@
 
 #ifdef STD_STRING_USES_COW
 #include <algorithm>
+#include <ostream>
 
 using namespace std;