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--- a/configure.ac
+++ b/configure.ac
@@ -8,6 +8,9 @@
 
 AM_INIT_AUTOMAKE([1.10 no-define subdir-objects foreign])
 
+if test X$CXXFLAGS = X;then
+   CXXFLAGS="-std=c++11 -g -O2"
+fi
 AC_PROG_CXX
 
 # ! Not sure that this is needed for upmpdcli and not only libupnpp