Hi Simon,

Thanks for the review.

> > +if test x"${enable_gdb}" != x"no"; then
> > +  # For this branch, we do not support building GDB in-tree.
> > +  # Try to detect whether we are in this situation or not by
> > +  # searching for a couple of known files in the source directory.
> > +  if test -f gnulib/update-gnulib.sh -a -f gdb/ChangeLog; then
> > +    AC_MSG_ERROR([GDB must be configured and built in a directory separate from its sources])
> 
> Finish the message with a period?

Of course! FWIW, I modeled this to other calls to AC_MSG_ERROR ;-)

> Some people who only know the "./configure && make && make install" recipe
> might not know how (or that it's even possible) to configure and build in a
> separate directory, so they'll be stuck there.  I think it would be helpful
> to give an example of how to do that, like:
> 
>     GDB must be configured and built in a directory separate from its sources.
> 
>     To do so, create a dedicated directory for your GDB build and invoke the configure
>     script from that directory:
> 
>       $ mkdir my-gdb-build
>       $ cd my-gdb-build
>       $ ../path/to/gdb-x.y.z/configure [configure args]
>       $ make
> 
> Otherwise, that looks good to me.

Attached is a revised patch. I chose to use the same sequence as
the one in gdb/README, just for consistency.

ChangeLog:

        * configure.ac: Abort the build with an error if trying to build
        GDB in tree.
        * configure: Regenerate.

For gdb-9-branch only... OK to push?

-- 
Joel