AC_FUNC_ALLOCA Is Screwing Me

[Drummonds, Scott B]

Hi, everyone,

Some of you more weary of my e-mails lately may recall that I've been
trying to figure out why Autoconf inserts a bunch (thousands of lines)
of code between a macro call and the first line in the macro.  I've
isolated the problem macro: AC_FUNC_ALLOCA.

I wrote the following macro and put it in my directory of m4
configuration files:

AC_DEFUN([TEST_SCOTT],[
  echo "In SCOTT"
  AC_FUNC_ALLOCA
])

I then inserted the following statement in configure.in:

...
echo "Calling SCOTT"
TEST_SCOTT
...

And, lo and behold, there are over 1300 lines of code that have been
inserted in the generated 'configure' script between the two echo
statements above.  Unfortunately, some of those statements are dependent
on $ac_objext, which has not yet been set in my environment.  Thus, this
environment is currently broken (although I will certainly look into
putting AC_FUNC_ALLOCA into a different area of the build configuration
to work around this problem.)

FWIW, I'm seeing the same behavior out of AC_CHECK_HEADERS.  Any time
that it is called in a macro I've defined some large amount of code is
inserted between the location where the macro was called and the first
line in the body of the macro.

What's going wrong here?  Why is this happening?  If this is a bug, how
do I go about submitting it to the Autoconf developers?

Scott