In the event that "swig" is not available, SWIG variable is blank, but the macro sets it to " -c++".
Further checks on SWIG variable, like:
if test "z$SWIG" != "z"
are passed even if "swig" is not available.
At some point a build procedure fails because it does not skip the part that requires "swig", and the command " -c++" is issued.
The macro can be fixed with a small patch: just change SWIG variable only if it's not blank.
address@hidden:~/lixa/m4include$ diff /home/tiian/autoconf-archive/m4/ax_swig_enable_cxx.m4 ax_swig_enable_cxx.m4
52c52,54
< SWIG="$SWIG -c++"
---
> if test "z$SWIG" != "z"; then
> SWIG="$SWIG -c++"
> fi
Kind Regards
Ch.F.