android-ndk has three binaries that are meant to live at the top
of it's keg tree, not in its bin. This commit creates the bin path
and symlinks those three binaries into its bin so that they will
be available to the user after install.
FixesHomebrew/homebrew#7514.
ClosesHomebrew/homebrew#7752.
Signed-off-by: Jack Nagel <jacknagel@gmail.com>