Compile errors when using libunwind

[richardeakin]

I have been trying out coffeecatch (thanks for the useful lib!) and noticed that it was trying to use corkscrew, while I need it to use libunwind as I'm targeting android 5.0+. So, I commended out the #define USE_CORKSCREW and then got the following compile errors:

src/android/coffeecatch.c: In function 'coffeecatch_copy_context':
src/android/coffeecatch.c:546:19: error: request for member 'absolute_pc' in something not a structure or union
       t->frames[i].absolute_pc = (uintptr_t) t->uframes[i];
                   ^
src/android/coffeecatch.c:547:19: error: request for member 'stack_top' in something not a structure or union
       t->frames[i].stack_top = 0;
                   ^
src/android/coffeecatch.c:548:19: error: request for member 'stack_size' in something not a structure or union
       t->frames[i].stack_size = 0;
                   ^
src/android/coffeecatch.c: In function 'coffeecatch_get_backtrace_info':
src/android/coffeecatch.c:1352:40: error: request for member 'absolute_pc' in something not a structure or union
       const uintptr_t pc = t->frames[i].absolute_pc;

Looks like t->frames is of type uintptr_t, is this part of the code still in need of an update?

Thanks again,
Rich