When using LTDL_INIT in configure, it causes -ldl to be added to LIBS, thus
later causing all the programs in a package (that uses ltdl) to be linked with dl, even if not
all would need it, see below.

I think it would be better if LIBLTDL would contain -ldl, and thus only programs
that actually use ltdl get linked with dl, and not all.

This happens because the LT_DLLOADERS macro uses AC_SEARCH_LIBS that sets LIBS, and
LIBS is not saved/restored before/after:
LIBADD_DLOPEN=
AC_SEARCH_LIBS([dlopen], [dl],
...
LT_DLLOADERS="$LT_DLLOADERS ${lt_dlopen_dir+$lt_dlopen_dir/}dlopen.la"])])])
if test x"$libltdl_cv_func_dlopen" = xyes || test x"$libltdl_cv_lib_dl_dlopen" = xyes
then
  lt_save_LIBS="$LIBS"
  LIBS="$LIBS $LIBADD_DLOPEN"
  AC_CHECK_FUNCS([dlerror])
  LIBS="$lt_save_LIBS"
fi

Here is a snippet from the output of 'sh -x ./configure':
+ LIBS=
+ printf '%s\n' 'configure:11758: result: -ldl'
+ printf '%s\n' -ldl
+ ac_res=-ldl
+ test -ldl '!=' no
+ test -ldl = 'none required'
+ LIBS='-ldl '
+ cat
+ test -ldl '!=' 'none required'
+ LIBADD_DLOPEN=-ldl
+ libltdl_cv_lib_dl_dlopen=yes
+ LT_DLLOADERS=' dlopen.la'
+ test x = xyes
+ test xyes = xyes
+ lt_save_LIBS='-ldl '

Also configure snippet:
if test "$ac_res" != no; then
  test "$ac_res" = "none required" || LIBS="$ac_res $LIBS"

cat >>confdefs.h <<\_ACEOF
#define HAVE_LIBDL 1
_ACEOF

	if test "$ac_cv_search_dlopen" != "none required" ; then
	  LIBADD_DLOPEN="-ldl"
	fi
...
if test x"$libltdl_cv_func_dlopen" = xyes || test x"$libltdl_cv_lib_dl_dlopen" = xyes
then
  lt_save_LIBS="$LIBS"

tags forwarded
thanks

Adding bug-libtool in Cc:, this should be fixed upstream.
(I'll look at it when I get back to Libtool, unless beaten to).

* Török Edwin wrote on Sat, Mar 14, 2009 at 03:16:30PM CET:

It doesn't seem to be fixed, I just checked latest snapshot.
Attached is a patch that fixes the problem (AC_SEARCH_LIBS sets LIBS, so
we must
save/restore LIBS before it, not only for AC_CHECK_FUNCS).

Best regards,
--Edwin