make compatible with automake >=1.13, distributions which no longer support indirect symbol resolution

automake >=1.13 runs tests in parallel mode by default; the old serial tests fail to run.  I've added the necessary automake option to use serial tests.

Many Linux distributions no longer support indirect symbol resolution (see https://wiki.debian.org/ToolChain/DSOLinking, https://wiki.ubuntu.com/NattyNarwhal/ToolchainTransition) which causes linking of lua.o against liblua.so to fail, as liblua.so did not explicitly link against libm and libdl.  I've added explicit dependencies to liblua.so