Also rename .visit() with .match() in MTP types.
Also add base::match_method() and base::match() for base::variant.
Also add base::match() and .match() for base::optional_variant.
To be able to run on the same distributions as before we need to have
the same GLIBC version dependency as in Ubuntu 12.04, which is 2.15.
For that we need to remove all usages of GLIBC features from 2.16 and above.
Currently there are three methods used, so they're wrapped in a separate
static library, linux_glibc_wraps.
It is a separate library because it must be compiled without '-flto' flag,
otherwise the inline __asm__ is not working and we get unresolved symbols.
John Preston