Index: src/makefile
--- src/makefile.orig	2018-10-14 10:49:22.986302000 +0200
+++ src/makefile	2018-10-14 10:51:21.882148000 +0200
@@ -8,7 +8,7 @@
 #CC=clang++
 
 # Added -std=c++11 because of auto_ptr to unique_ptr transition
-CXXFLAGS= -Wall -O2 -DNDEBUG -std=c++11 -fPIC
+CXXFLAGS= -O2 -DNDEBUG -std=c++11 -fPIC
 #CXXFLAGS= -O0 -ggdb -std=c++11 -fPIC
 #CXXFLAGS="-DNDEBUG -g2 -O3 -march=i686" 
 #cov-build --dir cov-int make -j 2
Index: src/rtfgenerator.cpp
--- src/rtfgenerator.cpp.orig	2018-10-12 22:04:07.000000000 +0200
+++ src/rtfgenerator.cpp	2018-10-14 10:49:22.986711000 +0200
@@ -29,6 +29,14 @@
 #include "rtfgenerator.h"
 #include "stylecolour.h"
 
+#include <sstream>
+
+template <typename T> std::string my_to_string(const T& n) {
+    std::ostringstream stm;
+    stm << n;
+    return stm.str();
+}
+
 namespace ansifilter
 {
 
@@ -179,7 +187,7 @@
     
     if (!utf8SeqLen){
       string m ( "\\u" );
-      m += to_string(utf16Char);
+      m += my_to_string(utf16Char);
       m += '?';
       utf16Char=0L;
       return m;
@@ -312,7 +320,7 @@
   std::istringstream iss(hexCode);
 
   iss >> std::hex >> x;    
-  decCode += to_string(x);
+  decCode += my_to_string(x);
   decCode +="?";
   
   return decCode;