backtrace.c: remove `MRB_API` from internal functions.
`mrb_exc_backtrace` to implement `Exception#backtrace`
`mrb_get_backtrace` to implement `#caller`
MODIFY
include/mruby/error.h
include/mruby/error.h
@@ -26,8 +26,9 @@ MRB_API mrb_value mrb_exc_new_str(mrb_state *mrb, struct RClass* c, mrb_value st
#define mrb_exc_new_lit(mrb, c, lit) mrb_exc_new_str(mrb, c, mrb_str_new_lit(mrb, lit))
#define mrb_exc_new_str_lit(mrb, c, lit) mrb_exc_new_lit(mrb, c, lit)
MRB_API mrb_value mrb_make_exception(mrb_state *mrb, mrb_int argc, const mrb_value *argv);
-MRB_API mrb_value mrb_exc_backtrace(mrb_state *mrb, mrb_value exc);
-MRB_API mrb_value mrb_get_backtrace(mrb_state *mrb);
+mrb_value mrb_exc_backtrace(mrb_state *mrb, mrb_value exc);
+mrb_value mrb_get_backtrace(mrb_state *mrb);
+
MRB_API mrb_noreturn void mrb_no_method_error(mrb_state *mrb, mrb_sym id, mrb_value args, const char *fmt, ...);
/* declaration for `fail` method */

MODIFY
src/backtrace.c
src/backtrace.c
@@ -221,7 +221,7 @@ mrb_unpack_backtrace(mrb_state *mrb, mrb_value backtrace)
return backtrace;
}
-MRB_API mrb_value
+mrb_value
mrb_exc_backtrace(mrb_state *mrb, mrb_value exc)
{
mrb_value backtrace;

backtrace.c: remove `MRB_API` from internal functions.

- `mrb_exc_backtrace` to implement `Exception#backtrace`
- `mrb_get_backtrace` to implement `#caller`