Remove the "AC_CONFIG_SUBDIRS(libltdl)" line. It fails with libtool 2.
tree6d6bf9d1b68d60025cdc0060bc1237c86b081bc8
-rw-r--r-- 3741 .gitignore
-rw-r--r-- 1453 .valgrind
drwxr-xr-x - ETL
drwxr-xr-x - autobuild
drwxr-xr-x - gtkmm-osx
drwxr-xr-x - synfig-core
drwxr-xr-x - synfig-docs
drwxr-xr-x - synfig-osx
drwxr-xr-x - synfig-studio