Feature request: hex literals

[Jeroen Demeyer <jdemeyer@cage.ugent.be>]

Since you're asking for possible feature requests: I'm surprised that
hex constants have never been implemented in PARI/GP, why cannot I do:

gp> 0xDEADBEEF
%1 = 3735928559

This looks like it should be easy to implement in the parser.

It can see at least two uses for this:
1) if you somehow need to store large numbers in a GP file, reading them
as hex digits would be faster than base 10.
2) copy/pasting pieces of \x output for debugging purposes.