Make sorting by basename fully deterministic

BasenameCompare() completely ignored leading directories.
While this is fine with respect to the zip files trrntzip creates,
the order of printed messages can differ when directory entries
get removed or re-zipping fails because of name clashes.

Compare the full paths of entries in case the basenames compare
equal to always ensure the same sort order and thus deterministic
output.

This should fix the flaky directories-2-d.test, so remove it from
XFAIL_TESTS on WIN32.

regress/CMakeLists.txt

@@ -4,7 +4,6 @@ if(WIN32)
   set(XFAIL_TESTS ${XFAIL_TESTS}
     cli-q.test
     cli-s.test
-    directories-2-d.test
     recurse.test
     recursive.test
   )

src/util.c

@@ -48,13 +48,19 @@ int StringCompare(const void *str1, const void *str2) {
   return CanonicalCmp(p1, p2);
 }
 
-// No tie-breaker for leading dirs required, names must be unique
 int BasenameCompare(const void *str1, const void *str2) {
   const char *p1 = *(const char **)str1;
   const char *p2 = *(const char **)str2;
   const char *b1 = strrchr(p1, '/');
   const char *b2 = strrchr(p2, '/');
-  return CanonicalCmp(b1 ? b1 + 1 : p1, b2 ? b2 + 1 : p2);
+  int res = CanonicalCmp(b1 ? b1 + 1 : p1, b2 ? b2 + 1 : p2);
+
+  // Tie-breaker ensures deterministic output. (It isn't needed for correct
+  // operation since names of added members must be unique.)
+  if (!res && b1 && b2)
+    res = CanonicalCmp(p1, p2);
+
+  return res;
 }
 
 int EndsWithCaseInsensitive(const char *str, const char *tail) {