Issue #26765: Ensure that bytes- and unicode-specific stringlib files are used
with correct type.
diff --git a/Objects/stringlib/codecs.h b/Objects/stringlib/codecs.h
index 2beb604..2846d7e 100644
--- a/Objects/stringlib/codecs.h
+++ b/Objects/stringlib/codecs.h
@@ -1,6 +1,8 @@
/* stringlib: codec implementations */
-#if STRINGLIB_IS_UNICODE
+#if !STRINGLIB_IS_UNICODE
+# error "codecs.h is specific to Unicode"
+#endif
/* Mask to quickly check whether a C 'long' contains a
non-ASCII, UTF8-encoded char. */
@@ -823,5 +825,3 @@
#undef SWAB4
#endif
-
-#endif /* STRINGLIB_IS_UNICODE */