fix crash

stepmania/src/archutils/Unix/BacktraceNames.cpp

@@ -127,7 +127,7 @@ void BacktraceNames::FromAddr( const void *p )
 			return;
     }
 
-    Symbol = di.dli_sname;
+    Symbol = di.dli_sname? di.dli_sname:"";
     File = di.dli_fname;
     Offset = (char*)(p)-(char*)di.dli_saddr;
 }

stepmania/src/archutils/Unix/CrashHandlerChild.cpp

@@ -51,7 +51,7 @@ static void output_stack_trace( FILE *out, const void **BacktracePointers )
 		bn.Demangle();
 		
 		/* Don't show the main module name. */
-		if( bn.File == g_pCrashHandlerArgv0 )
+		if( bn.File == g_pCrashHandlerArgv0 && !bn.Symbol.empty() )
 			bn.File = "";
 		
 		if( bn.Symbol == "__libc_start_main" )