-
-AC_LTDL_ENABLE_INSTALL
-AC_LIBLTDL_INSTALLABLE
-AC_LIBTOOL_DLOPEN
-AC_LIBTOOL_WIN32_DLL
-AC_PROG_LIBTOOL
-AC_SUBST(LTDLINCL)
-AC_SUBST(LIBLTDL)
-AC_CONFIG_SUBDIRS(libltdl)
-
-old_LIBS=$LIBS
-LIBS="$LIBS $LIBLTDL"
-AC_CHECK_FUNCS([lt_dlmutex_register])
-LIBS=$old_LIBS
-AC_CHECK_TYPES([struct lt_user_dlloader, lt_dladvise], , , [#include <ltdl.h>])
-
-if test "x$enable_ltdl_install" = "xno" && test "x$ac_cv_lib_ltdl_lt_dlinit" = "xno" ; then
- AC_MSG_ERROR([[
-
- *** Cannot find the libltdl development files.
- *** Maybe you need to install the libltdl-dev package.
- ]])
-fi
+LT_PREREQ(2.2)
+LT_INIT([dlopen win32-dll disable-static])
+
+dnl Unfortunately, even up to libtool 2.2.6a there is no way to know
+dnl exactly which version of libltdl is present in the system, so we
+dnl just assume that it's a working version as long as we have the
+dnl library and the header files.
+dnl
+dnl As an extra safety device, check for lt_dladvise_init() which is
+dnl only implemented in libtool 2.x, and refine as we go if we have
+dnl refined requirements.
+dnl
+dnl Check the header files first since the system may have a
+dnl libltdl.so for runtime, but no headers, and we want to bail out as
+dnl soon as possible.
+dnl
+dnl We don't need any special variable for this though, since the user
+dnl can give the proper place to find libltdl through the standard
+dnl variables like LDFLAGS and CPPFLAGS.
+
+AC_CHECK_HEADER([ltdl.h],
+ [AC_CHECK_LIB([ltdl], [lt_dladvise_init], [LIBLTDL=-lltdl], [LIBLTDL=])],
+ [LIBLTDL=])
+
+AS_IF([test "x$LIBLTDL" = "x"],
+ [AC_MSG_ERROR([Unable to find libltdl.])])
+AC_SUBST([LIBLTDL])