Allow disabling pretty traces and remove dependency on libdw.

src/Exception.hpp

@@ -6,7 +6,9 @@
 #include <string>
 #include <utility>
 #if !WINDOWS
+#if PRETTYTRACES
 #define BACKWARD_HAS_DW 1
+#endif
 #include "../extern/backward.hpp"
 #endif
 
@@ -53,6 +55,9 @@ namespace ArbUt {
                 backward::ResolvedTrace trace = tr.resolve(_stack[i]);
                 if (trace.source.filename.empty()) {
                     AppendNoSourceStack(ss, trace, include_addr);
+                    if (foundExceptionClass) {
+                        framesAppended++;
+                    }
                 } else {
                     AppendSourceStack(ss, trace.source, foundExceptionClass, snippetFactory);
                     if (foundExceptionClass) {