export numa_init

Hello,

when I compile latest libnuma.so, the numa_init symbol is not exported.
So it is not possible to linked against this lib with code which called
numa_init directly from code. One of affected program is HipHop Virtual
Machine (HHVM)
https://github.com/facebook/hiphop-php/blob/master/hphp/util/alloc.cpp#L135

So it is possible to add numa_init into global section in
versions.ldscript?

With kind regards

Daniel Kozak