Download waf (https://waf.io/)

autowaf.py is present in the tools directory of the Ardour source code.
a patch for C++11/clang can be found in tools/waflib.patch (needed for waf 1.8.19)

Current waf is build as follows;

ARDOURSRC=`pwd`
cd /tmp
curl https://waf.io/waf-1.6.11.tar.bz2 | tar xj
cd waf-1.6.11

patch -p1 < $ARDOURSRC/tools/waflib.patch
./waf-light -v --make-waf --tools=misc,doxygen,$ARDOURSRC/tools/autowaf.py --prelude=''
cp ./waf $ARDOURSRC/waf