adb: fix stat on Windows.

stat on Windows fails with ENOENT when passed a path with a trailing
slash or backslash, regardless of whether the target is actually a
directory. Emulate the correct POSIX behavior by stripping trailing
path separators and then checking if the target is a directory if
successful.

Bug: http://b/30481559
Bug: https://code.google.com/p/android/issues/detail?id=214633
Change-Id: I1d398d19a9bce1ecb3fdc4aabc31aa98c82c3f93
Test: Relevant adb_tests pass on Linux and Windows 10.
diff --git a/adb/sysdeps.h b/adb/sysdeps.h
index 212c1c3..04df16f 100644
--- a/adb/sysdeps.h
+++ b/adb/sysdeps.h
@@ -34,6 +34,8 @@
 #include <android-base/unique_fd.h>
 #include <android-base/utf8.h>
 
+#include "sysdeps/stat.h"
+
 /*
  * TEMP_FAILURE_RETRY is defined by some, but not all, versions of
  * <unistd.h>. (Alas, it is not as standard as we'd hoped!) So, if it's
@@ -199,8 +201,6 @@
     /* nothing really */
 }
 
-#define  lstat    stat   /* no symlinks on Win32 */
-
 #define  S_ISLNK(m)   0   /* no symlinks on Win32 */
 
 extern int  adb_unlink(const char*  path);
@@ -307,27 +307,6 @@
     return isalpha(path[0]) && path[1] == ':' && path[2] == '\\';
 }
 
-// We later define a macro mapping 'stat' to 'adb_stat'. This causes:
-//   struct stat s;
-//   stat(filename, &s);
-// To turn into the following:
-//   struct adb_stat s;
-//   adb_stat(filename, &s);
-// To get this to work, we need to make 'struct adb_stat' the same as
-// 'struct stat'. Note that this definition of 'struct adb_stat' uses the
-// *current* macro definition of stat, so it may actually be inheriting from
-// struct _stat32i64 (or some other remapping).
-struct adb_stat : public stat {};
-
-static_assert(sizeof(struct adb_stat) == sizeof(struct stat),
-    "structures should be the same");
-
-extern int adb_stat(const char* f, struct adb_stat* s);
-
-// stat is already a macro, undefine it so we can redefine it.
-#undef stat
-#define stat adb_stat
-
 // UTF-8 versions of POSIX APIs.
 extern DIR* adb_opendir(const char* dirname);
 extern struct dirent* adb_readdir(DIR* dir);