GetModuleFileName() hang during signal processing

[Joe Buehler]

Checking the address range in interruptible() to prevent the call
to GetModuleFileName() does indeed fix the ksh93 hang problem.

I will submit a patch to exceptions.cc in a bit.

Right now I am assuming anything in the 0x7xxxxxxx address
range is a Microsoft DLL.  Is that a valid assumption for all
Windows platforms?
-- 
Joe Buehler