Update ICU to 58.3

- This adds the new Japanese ascension era (Reiwa)
- This updates timezone data to 2019a
- Updated script for git instead of SVN
- Regenerated locale data

intl/icu/source/common/umutex.h

@@ -86,9 +86,7 @@ U_NAMESPACE_END
 //                Original plan was to use gcc atomics for MinGW, but they
 //                aren't supported, so we fold MinGW into this path.
 
-# ifndef WIN32_LEAN_AND_MEAN
 # define WIN32_LEAN_AND_MEAN
-# endif
 # define VC_EXTRALEAN
 # define NOUSER
 # define NOSERVICE
@@ -333,9 +331,7 @@ U_NAMESPACE_END
  *         win32 APIs for Critical Sections.
  */
 
-# ifndef WIN32_LEAN_AND_MEAN
 # define WIN32_LEAN_AND_MEAN
-# endif
 # define VC_EXTRALEAN
 # define NOUSER
 # define NOSERVICE