I was trying to debug why a GCC 14 build of tcl 8.6.16 broke any use of floating point, for example:

```
$ tclsh
% expr rand()
wrong digit!
Abort (core dumped)
```

It turned out, after comparing against an earlier GCC 13 build, that the GCC 14 build was incorrectly being built with `-DWORDS_BIGENDIAN=1`, and this is because the configure test for endianness is now broken:

```
-conftest.c:54:3: warning: implicit declaration of function 'exit' [-Wimplicit-function-declaration]
+conftest.c:54:3: error: implicit declaration of function 'exit' [-Wimplicit-function-declaration]
    54 |   exit (u.c[sizeof (long) - 1] == 1);
       |   ^~~~
```

The failure to compile conftest is being interpreted as the _test itself_ failing, thus determining that this x86_64 platform is now suddenly big endian, leading to sub-optimal behaviour.

I'd recommend throwing GCC 14 in the bin for causing such disgustingly insidious fallout, but you may want to implement a more grown-up solution, such as the one I committed to pkgsrc [here](https://github.com/NetBSD/pkgsrc/commit/cf369163c379e6cbdeafd7b0229ca72583d46be8)

Thanks.

> Would not something like this help?

What about people who deliberately are doing a autoreconf to force installation of the manpages in /usr/share/man*? That won't work the same any more.

It's not worth the effort.

Would not something like this help?
```
mandir=${prefix}/man
AC_SUBST(mandir)
```

> TCT is very conservative here for whatever reason (@Jan, why?!)

The reason for this is a change in autoconf-2.60:

  The following variables have new default values:

datadir       read-only architecture-independent data [DATAROOTDIR]
    infodir       info documentation [DATAROOTDIR/info]
    mandir        man documentation [DATAROOTDIR/man]

The effect of this is that autoconf-2.59 has "mandir = ${prefix}/man", while autoconf-2.60+ has "mandir = ${datarootdir}/man" which resolves to "mandir = ${prefix}/share/man". So, if update the "configure" script, the man-pages will suddenly install in a different directory than before. That's not expected in a patch release, even though it is following the "GNU coding standards".

So, we have to live with a manual "configure" patch for a while. Since the support for 8.6 is going to end soon anyway, I can live with that.

Well, it is known obsolescence and basically is a result of standard autoconf macro `AC_C_BIGENDIAN`, which is in case of 8.6 a bit outdated, because `unix/configure` is built with autoconf 2.59 and TCT is very conservative here for whatever reason (@Jan, why?!).

IIRC, the macro was fixed somewhere in autoconf 2.69 (it'll also check preprocessor directives now instead of naive byte comparison and so better suitable for cross-compile, etc)... Anyway, autoconf 2.71 does the job correct.

The only option you have now - is to rebuild `configure` by yourself, e. g. invoke `autoreconf -f` in `unix` directory before starting `configure`.
I'd always recommend it as long as the autoconf/automake is installed and still compatible with obsolete macros like `AC_HEADER_TIME`.