avoid locale-dependent unit test

mle.h

@@ -700,6 +700,7 @@ TODO major changes
 [ ] rewrite srules (complex/unreadable; use_srules sucks; overlapping multi srules bug; make stateful, e.g., in-string, in-comment)
 [ ] rewrite/generalize aproc+menu (too tightly coupled; a better solution possibly supersedes dte's errorfmt/compile)
 [ ] rewrite buffer_set_mmapped to avoid huge mallocs
+[ ] use wcwidth9 autc instead of relying on locale and wcwidth (tests/unit/test_bline_insert.c)
 TODO bugfixes
 [ ] review error checking, esp catch ENOSPC, malloc fail
 [ ] review compiler warnings

tests/unit/test_bline_insert.c

@@ -27,7 +27,14 @@ void test(buffer_t *buf, mark_t *cur) {
     ASSERT("oob", 0, strncmp(data, "hello\namy's\n world", data_len));
 
     bline_insert(buf->last_line, buf->last_line->char_count, "\nno\xe2\x80\x8bspace", 11, NULL);
-    ASSERT("0wv", 7, buf->last_line->char_vwidth);
+    // The following assertion relies on a UTF-8 locale. `nl_langinfo` may not
+    // be available, so let's comment it out for now. (In practice, if locale
+    // is, e.g., C, the zero-width space will show up as "?" with vwidth==1.)
+    //
+    // codeset = nl_langinfo(CODESET);
+    // if (codeset && strcmp(codeset, "UTF-8") == 0) {
+    //     ASSERT("0wv", 7, buf->last_line->char_vwidth);
+    // }
     ASSERT("0wc", 8, buf->last_line->char_count);
     ASSERT("0wd", 10, buf->last_line->data_len);