PARI/GP for Windows doesn't support umlauts and diacritical signs but it's possible

[Jens Schmidt <crashdump@meine-dateien.info>]

PARI/GP for Windows only supports ASCII chars in input and output. The
programm should set the both codepages for input and output to the
default value given by Windows registry (called ACP: ANSI codepage).
That is easily done by some C code at startup:

  SetConsoleCP( GetACP() );
  SetConsoleOutputCP( GetACP() );

By default the codepage of a Windows console is set to ancient DOS 437
or 850,... called OEMCP. These old OEM codepages aren't recommend.

ACP is CP 1252 by default (aka Western) which is nearly identical to
ISO-8859-1 and UTF-8 (Latin1 block). Windows uses some of the characters
0x80 .. 0x9f which are non-printable chars in ISO-8859-1 and UTF-8.

Windows has very limited support for UTF-8 console (codepage 65001).
UTF-8 file/console redirect isn't possible because Windows doesn't
support multibyte file IO - only single byte and wide chars.

I've tested this with Windows 7 and Wine in Linux. Setting codepages
functions too through a PARI/GP plugin which could be installed at any
time and would make older versions working.