Do not redefine _FILE_STAT_LX_INFORMATION (git-for-windows#5092)

The struct definition as well as the other defines are already defined
in Windows SDK >= 10.1.26100.1.

Author: dscho

compat/win32/wsl.c

@@ -54,6 +54,7 @@ int copy_wsl_mode_bits_from_disk(const wchar_t *wpath, ssize_t wpathlen,
 	return ret;
 }
 
+#ifndef LX_FILE_METADATA_HAS_UID
 #define LX_FILE_METADATA_HAS_UID 0x1
 #define LX_FILE_METADATA_HAS_GID 0x2
 #define LX_FILE_METADATA_HAS_MODE 0x4
@@ -78,6 +79,7 @@ typedef struct _FILE_STAT_LX_INFORMATION {
 	uint32_t LxDeviceIdMajor;
 	uint32_t LxDeviceIdMinor;
 } FILE_STAT_LX_INFORMATION, *PFILE_STAT_LX_INFORMATION;
+#endif
 
 /*
  * This struct is extended from the original FILE_FULL_EA_INFORMATION of