waf: Change the executables path
waf: Change the executables path

Meson and CMake place output binaries in the same directory structure
as source directory.  Follow the pattern so that we can unify the
buildall.py implementation.

Signed-off-by: Yasushi SHOJI <afa9ca3be149447780c2f7b524d61ed3d3db63f9@spacecubics.com>

libcsp/libcsp,libcsp/libcsp