This patch checks for, and provides the display of, compiler errors for custom patches. When a compilation error is detected a
Display Compiler Errors
button is made visible. When this button is pressed there's a dialog to display the errors.
The line numbers are not correct; that could probably be fixed. But, at least for me, it's vastly improved behavior.
The patch is a little ugly; I wanted to minimize changes to how the compiler is invoked and it's partly due to the interactions with stuff in NB. I was going to return custom ProblemDetails but the class is final.
I apply this patch after the patch in issue 17.