Rename __libc_init to _libc_init and call it explicitly from CSU code.
This enforces the constructor run order for newly linked programs.
Keep it as constructor with run-once semantic for binary compatibility.
Implement dl_iterate_phdr for statically linked programs.
This material is based upon work partially supported by
The NetBSD Foundation under a contract with Joerg Sonnenberger.
for weak references. GCC 4.2+ and Clang require static, older GCC wants
extern. Change __weak_reference to include sym. This requires changes
the existing users to not reuse the name of the symbol, but avoids
further differences between GCC 4.1 and GCC 4.2+/clang.
