runtime: call execname and getpagesize on Solaris

Interpreting auxv as []uintptr is incorrect on 64-bit big-endian,
as auxv alternates a 32-bit int with a 64-bit pointer.

Patch from Rainer Orth.

Change-Id: I4edfb7bee85de397aa2ef1296976d3ca9b177066
Reviewed-on: https://go-review.googlesource.com/c/164739
Reviewed-by: Ian Lance Taylor <iant@golang.org>
1 file changed