[LLVM][Cygwin] Fix Signals compatibility with Cygwin API

Author: mati865

llvm/lib/Support/Unix/Signals.inc

@@ -847,7 +847,7 @@ void llvm::sys::PrintStackTrace(raw_ostream &OS, int Depth) {
 
     const char *name = strrchr(dlinfo.dli_fname, '/');
     if (!name)
-      OS << format(" %-*s", width, dlinfo.dli_fname);
+      OS << format(" %-*s", width, (const char *)dlinfo.dli_fname);
     else
       OS << format(" %-*s", width, name + 1);