Make sure GLRO(dl_pagesize) is initialized properly on all archs

Make sure GLRO(dl_pagesize) is initialized properly on all archs

After a recent change to __getpagesize(), GLRO(dl_pagesize) is required
to be set.  But that is only done at app init, and shared libraries
dlopened at runtime by static apps dont have their GLRO() state
initialized from the linux auxvec.

ia64/mips have long had similar behavior with their __getpagesize(), but
they have a DL_STATIC_INIT hook to sync some of the static GLRO() fields
to the dynamic GLRO() fields.  Now that common linux code requires
GLRO(dl_pagesize) to be set, common linux code now needs that
DL_STATIC_INIT hook.

This patch takes the ia64 logic and promotes it to common code.