circular library dependencies

[Eric Blake]

This week, gnulib moved to the scenario where it will create circular library 
dependencies.  For example, on branch-1_4 of m4, when compiling the test 
program tests/test-gl_array, lib/libm4.a depends on program_name provided by 
progname.o in tests/libtests.a, but tests/libtests.a depends on xmalloc 
provided by xalloc.o in lib/libm4.a.  So the solution was to make gnulib output 
the same library twice on the link line.

But now with m4 head, this is tripping up libtool, which doesn't respect 
circular library dependencies:

/bin/sh ../../libtool --tag=CC   --mode=link gcc -std=gnu99  -gdwarf-2 -Wall -
Werror   -o test-array_list.exe test-array_list.o 
libtests.a  ../../gnu/libgnu.la libtests.a  /usr/local/lib/libintl.dll.a -
liconv -L/usr/local/lib 
libtool: link: gcc -std=gnu99 -gdwarf-2 -Wall -Werror -o .libs/test-
array_list.exe test-array_list.o  ../../gnu/.libs/libgnu.a 
libtests.a /usr/local/lib/libintl.dll.a /usr/lib/libiconv.dll.a -L/usr/local/lib
libtests.a(gl_array_list.o): In function `gl_array_create_empty':
../../../tests/gnu/gl_array_list.c:61: undefined reference to `_xmalloc'

Even though libtests.a was properly specified both before and after 
gnu/libgnu.la in the original tool, libtool discarded the first instance of 
libtests.a when generating the link command, leading to link failure.

How do we go about solving this?

-- 
Eric Blake