feat(gblibc): add ferror_unlocked

gblibc/include/stdio.h

@@ -57,6 +57,7 @@ int fgetc(FILE* stream);
 int fputc(int character, FILE* stream);
 
 int ferror(FILE* stream);
+int ferror_unlocked(FILE* stream);
 int feof(FILE* stream);
 void clearerr(FILE* stream);
 

gblibc/src/stdio.c

@@ -792,6 +792,12 @@ int fgetc(FILE* stream)
 }
 
 int ferror(FILE* stream)
+{
+    // TODO: lock the stream
+    return ferror_unlocked(stream);
+}
+
+int ferror_unlocked(FILE* stream)
 {
     return stream->flags & FILE_ERROR;
 }