Compiler should report IOExceptions as regular errors rather than internal compiler errors

Steps to reproduce:
1. Compile a swf with Flash Builder
2. Make the swf unwritable – e.g. on Mac, do "chmod -w myfile.swf"
3. Compile it again with Flash Builder

Actual Results:
Flash Builder reports an "internal compiler error" in the Problems view. I haven't had a chance to try a command-line build, but I imagine the results are similar: It probably shows a callstack, as if an unexpected exception occurred.

Expected Results:
The compiler should log IOExceptions as regular build errors rather than throwing exceptions, because it is not uncommon to have file permission errors of various kinds when writing to the swf. E.g. on Windows, it might make sense for this to show up as "The process cannot access the file because it is being used by another process" (which is, I think, the getMessage() text of the IOException).