Fix ssize_t, WCHAR_MIN and WCHAR_MAX

1) ssize_t is int, instead of long int
2) WCHAR_MIN and WCHAR_MAX be consistent with bionic's:
   respond to __WCHAR_UNSIGNED__, work for both signed (X86/MIPS)
   and unsigned (ARM) wchar_t, and work for -fshort-wchar too

Change-Id: Ief1be007571b50c5d63a819df489f9d3f9b47bc8
3 files changed