I restart this thread.
So, what I would like to do is checking Mac OS X headers in an m4 macro. If
the objective C compiler is installed, no problem. If it is not, i would like
that, in the m4 macro, the test not to be done.
I have attached a complete, and I think, minimal example
In configure.ac, I call conditionnaly AC_PROG_OBJC.
Before using AC_CHECK_HEADER in check.m4, I have to call
AC_LANG_PUSH([Objective C]). It is that macro that is the problem:
1) Without it and on a system without an obj c compiler, no problem.
2) Without it and on a system with an obj c compiler, there is an error.
3) With it and on a system without an obj c compiler there is an error
4) With it and on a system with an obj c compiler, no problem
as there is a failure in point 2), I must use AC_LANG_PUSH([Objective C])
What must I do, in check.m4, to disable the check of those headers, so that
there is no problem with AC_LANG_PUSH([Objective C]) (point 3) ) ?