Show stackTrace on asserts

config.nims

@@ -1,9 +1,4 @@
-#[
-see D20190127T231316 workaround for fact that toast needs to build
-scanner.cc, which would otherwise result in link errors such as:
-"std::terminate()", referenced from:
-      ___clang_call_terminate in scanner.cc.o
-]#
+# Workaround for C++ scanner.cc causing link error with other C obj files
 when defined(MacOSX):
   switch("clang.linkerexe", "g++")
 else:
@@ -11,4 +6,7 @@ else:
 
 # Workaround for NilAccessError crash on Windows #98
 when defined(Windows):
-  switch("gc", "markAndSweep")
+  switch("gc", "markAndSweep")
+
+# Retain stackTrace for clear errors
+switch("stackTrace", "on")