Remove libtool (introduced with spglib 1.9.9)
Do not use libtool in Octopus nor spglib. This causes a lot of issues with compilation.
spglib should be a non-installed library.
Do not link -lm explicitly.
Older versions of autotools cannot run a command to parse the version number, so give it explicitly.
This enables Octopus to be compiled on Blue Gene/Qs.