autoconf-2.59b fails to include correct X11R6 paths in configure scripts on AMD64 systems

[Nelson H. F. Beebe]

The latest release of autoconf-2.59b, dated 28-Dec-2005, fails to
include correct X11R6 paths in configure scripts on AMD64 systems
running GNU/Linux.

Those machines support both a 32-bit world and a default 64-bit world.
For the latter, libraries are found in directories that end in 64:
/lib64, /usr/lib64, /usr/X11R6/lib64, ...  While the linker knows
about the first two, it doesn't know about the X11R6 tree.

The configure script generated by autoconf contains these directories
(here, in the new xterm-203 distribution from
ftp://invisible-island.net/xterm/xterm.tar.gz):

        % grep '/X11' configure | tr -d ' \\' | sort -u | grep '^/' | pr -t -c2
        /lib/usr/lib/X11                    /usr/local/X11/lib
        /usr/include/X11                    /usr/local/X11R4/include
        /usr/include/X11R4                  /usr/local/X11R4/lib
        /usr/include/X11R5                  /usr/local/X11R5/include
        /usr/include/X11R6                  /usr/local/X11R5/lib
        /usr/lib/X11                        /usr/local/X11R6/include
        /usr/lib/X11R4                      /usr/local/X11R6/lib
        /usr/lib/X11R5                      /usr/X11/include
        /usr/lib/X11R6                      /usr/X11/lib
        /usr/local/include/X11              /usr/X11R4/include
        /usr/local/include/X11R4            /usr/X11R4/lib
        /usr/local/include/X11R5            /usr/X11R5/include
        /usr/local/include/X11R6            /usr/X11R5/lib
        /usr/local/lib/X11                  /usr/X11R6/include
        /usr/local/lib/X11R4                /usr/X11R6/lib
        /usr/local/lib/X11R5                /usr/XFree86/include/X11
        /usr/local/lib/X11R6                /usr/XFree86/lib/X11
        /usr/local/X11/include

Notice that the X11R6/include directories are listed, as are the
X11R6/lib ones, but the X11R6/lib64 directories are absent.

This defect in autoconf has caused a number of GNU and non-GNU
packages to fail to build on GNU/Linux AMD64 systems with the
canonical recipe

        ./configure && make all check install

In most cases, it is possible do a manual override, like this

        env LDFLAGS='-L/usr/X11R6/lib64 -Wl,-rpath,/usr/X11R6/lib64' 
./configure && \
                make all check install

but the nuisance is that the -Wl option may be compiler dependent, and
in any event, it goes against the goal of autoconf of providing a
simple standard way to build software everywhere.

-------------------------------------------------------------------------------
- Nelson H. F. Beebe                    Tel: +1 801 581 5254                  -
- University of Utah                    FAX: +1 801 581 4148                  -
- Department of Mathematics, 110 LCB    Internet e-mail: address@hidden  -
- 155 S 1400 E RM 233                       address@hidden  address@hidden -
- Salt Lake City, UT 84112-0090, USA    URL: http://www.math.utah.edu/~beebe  -
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