Dynamic Linker Fixes
  1- Remove deps on libsupc++ for linker
  2- Fix missing symbol in dnfc dl_irt_ptr
  3- Add setjmp/longjump
  4- Add -Ttext-section=0x10000
  5- Add cmake builder script
  6- Add missing weak/strong ref macros
  7- Fix linker and libc Makefiles use of NACL_ARCH and GCC_ARCH
  8- Fix 32->64 bit issues in link.h (Elf64_Addr)

Fixes allow us to build both static and dynamic i686, however
dynamic i686 stillf fails with linker reloc issues.