Simplify code. Drop support for Borland C++ on Windows.
* gettext-runtime/intl/dcigettext.c: Simplify
'defined _WIN32 || defined __WIN32__' to just 'defined _WIN32'.
* gettext-runtime/intl/l10nflist.c: Likewise.
* gettext-runtime/intl/langprefs.c: Likewise.
* gettext-runtime/intl/libgnuintl.in.h: Likewise.
* gettext-runtime/intl/loadinfo.h: Likewise.
* gettext-runtime/intl/setlocale.c: Likewise.
* gettext-runtime/intl/printf-parse.c: Likewise.
* gettext-runtime/libasprintf/printf-parse.c: Likewise.
* gettext-tools/src/format-c-parse.h: Likewise.
* gettext-tools/src/hostname.c: Likewise.
* gnulib-local/lib/basename.c: Likewise.
