Prepare zucchini sources for mingwclang builds

- base/files/file_util_win.cc: OpenFile() uses _SH_DENYNO, which the MSVC CRT
  headers happen to expose transitively but mingw-w64 only declares in
  <share.h>.

- base/base_paths_win.cc: <KnownFolders.h> is not found when cross-compiling,
  as mingw-w64 spells the header knownfolders.h and the build host can have a
  case-sensitive filesystem. Its only user, FOLDERID_ApplicationShortcuts in
  the DIR_APP_SHORTCUTS case is already excluded under MOZ_ZUCCHINI.

- components/zucchini/suffix_array_unittest.cc: libc++ ships no
  std::char_traits<unsigned char> specialization, so
  std::basic_string<unsigned char> cannot be instantiated. The test only ever
  uses the alias as a sized random-access container (construction from an
  iterator pair, begin/end/size), so under MOZ_ZUCCHINI it becomes
  std::vector<unsigned char>.
---
 base/base_paths_win.cc                       | 2 ++
 base/files/file_util_win.cc                  | 3 +++
 components/zucchini/suffix_array_unittest.cc | 4 ++++
 3 files changed, 9 insertions(+)

diff --git a/base/base_paths_win.cc b/base/base_paths_win.cc
index ce7ce4b6899e..467dcb5ee297 100644
--- a/base/base_paths_win.cc
+++ b/base/base_paths_win.cc
@@ -4,7 +4,9 @@
 
 #include <windows.h>
 
+#if !defined(MOZ_ZUCCHINI)
 #include <KnownFolders.h>
+#endif  // !defined(MOZ_ZUCCHINI)
 #include <shlobj.h>
 
 #include "base/base_paths.h"
diff --git a/base/files/file_util_win.cc b/base/files/file_util_win.cc
index bd2082584525..251c683da9c0 100644
--- a/base/files/file_util_win.cc
+++ b/base/files/file_util_win.cc
@@ -8,6 +8,9 @@
 
 #include <io.h>
 #include <psapi.h>
+#if defined(MOZ_ZUCCHINI)
+#include <share.h>
+#endif  // defined(MOZ_ZUCCHINI)
 #include <shellapi.h>
 #include <shlobj.h>
 #include <stddef.h>
diff --git a/components/zucchini/suffix_array_unittest.cc b/components/zucchini/suffix_array_unittest.cc
index 57775b047ea1..abf2137ad607 100644
--- a/components/zucchini/suffix_array_unittest.cc
+++ b/components/zucchini/suffix_array_unittest.cc
@@ -22,7 +22,11 @@ using SLType = InducedSuffixSort::SLType;
 
 }  // namespace
 
+#if defined(MOZ_ZUCCHINI)
+using ustring = std::vector<unsigned char>;
+#else
 using ustring = std::basic_string<unsigned char>;
+#endif  // defined(MOZ_ZUCCHINI)
 
 constexpr uint16_t kNumChar = 256;
 
-- 
2.53.0