Summary:
Bionic doesn't initialize its globals early enough. This causes issues when
trying to access them from a preinit_array (b/25751302) or from another
constructor called before the libc one (b/68046352). __progname is initialized
after the other globals, so we can check its value to know if calling
`getauxval` is safe.
Reviewers: alekseyshl
Reviewed By: alekseyshl
Subscribers: srhines, llvm-commits
Differential Revision: https://reviews.llvm.org/D40504
llvm-svn: 319099