Name should be an atom (single quotes), not a string (double quotes). The current code works by accident, but could stop doing so in future releases of Erlang/OTP. See http://erlang.org/doc/man/code.html#lib_dir-1
diff --git a/lib/autoconf/erlang.m4 b/lib/autoconf/erlang.m4 index c757cd1..d188f34 100644 --- a/lib/autoconf/erlang.m4 +++ b/lib/autoconf/erlang.m4 @@ -180,7 +180,7 @@ AC_CACHE_CHECK([for Erlang/OTP '$1' library subdirectory], [AC_LANG_PUSH(Erlang)[]dnl AC_RUN_IFELSE( [AC_LANG_PROGRAM([], [dnl - ReturnValue = case code:lib_dir("[$1]") of + ReturnValue = case code:lib_dir('[$1]') of {error, bad_name} -> file:write_file("conftest.out", "not found\n"), 1;