This file describes the directory layout of the PNaCl toolchain.

The most important thing is the user-facing toolchain programs, including
pnacl-clang, pnacl-clang++, pnacl-translate, etc. These are located in
the bin/ directory. The location (and existence) of everything else is subject
to change.

bin/
  User-facing toolchain programs (pnacl-clang, pnacl-translate, etc).
  Currently these are OS-specific wrapper scripts.
host_x86_32/
  Executable toolchain binaries for x86-32 hosts. These are not intended to be
  run directly; use the wrapper scripts in bin/
host_x86_32/
  Executable toolchain binaries for x86-64 hosts. These are not intended to be
  run directly; use the wrapper scripts in bin/
lib-arm/
  Native NaCl object files and/or libraries linked into ARM nexes after
  offline translation.
lib-mips32/
  Native NaCl object files and/or libraries linked into MIPS nexes after
  offline translation.
lib-x86-32/
  Native NaCl object files and/or libraries linked into x86-32 nexes after
  offline translation.
lib-x86-64/
  Native NaCl object files and/or libraries linked into x86-64 nexes after
  offline translation.
lib/
  Bitcode object files and/or libraries linked into user-generated pexes
sdk/
  Libraries and headers provided by the NaCl SDK which are not packaged with
  the toolchain itself
usr/
  Libraries and headers packaged with the toolchain (e.g. libc, libm, libstdc++)
  Naclports also installs its libraries and headers here.
tools-arm/
  Native ARM binaries used for testing (e.g. the standalone NaCl loader)
tools-x86/
  Native x86 binaries used for testing (e.g. x86 version of the ARM validator)
