title: dynamically link one lib to another lib at build time, yet link statically into iphone app
body: <p>i've got a lib, A, which can be linked into an iPhone app by itself. i'd like to make 2 other libs, B and C, which depend on A.</p>
  
  <p>an app may want to be built by linking the libs statically in any of these combinations: A, A+B, A+C, or A+B+C.</p>
  
  <p>however, when building B or C, i'd like them to link to their dependent lib A dynamically, e.g. B depends on A but does not copy A into itself statically. is this possible?</p>
  
  <p>note: i'm not asking if libs can dynamically link into apps. i'm trying to find out if libs can be dynamically linked to another at compile time, such that the lib does not contain a copy of its dependent lib inside of itself. but at when building an app, the user can statically link any of the above allowable combinations above.</p>