Fixed cc65 exitcode when there are only preprocessor errors.

src/cc65/main.c

@@ -1089,7 +1089,7 @@ int main (int argc, char* argv[])
     Compile (InputFile);
 
     /* Create the output file if we didn't had any errors */
-    if (PreprocessOnly == 0 && (ErrorCount == 0 || Debug)) {
+    if (PreprocessOnly == 0 && (GetTotalErrors () == 0 || Debug)) {
 
         /* Emit literals, do cleanup and optimizations */
         FinishCompile ();
@@ -1115,5 +1115,5 @@ int main (int argc, char* argv[])
     DoneSegAddrSizes ();
 
     /* Return an apropriate exit code */
-    return (ErrorCount > 0)? EXIT_FAILURE : EXIT_SUCCESS;
+    return (GetTotalErrors () > 0)? EXIT_FAILURE : EXIT_SUCCESS;
 }

test/err/bug2312-pperror-only.c

@@ -0,0 +1,8 @@
+/* Bug #2312 */
+
+#error "Compiler should exit with failure"
+
+int main(void)
+{
+    return 0;
+}