indent(1): rewrite the integer/floating constant scanning part of lexi.c

Remove procedural code that did the scanning, which was faulty and didn't
support complex constants such as 0x1p-61. Replace it with a finite state
machine expressed as a transition table. The table was rewritten by hand
from lx's output, given parts of grammar expressed as regular expressions.

lx is Katherine Flavel's lexer generator, currently available at
https://github.com/katef/libfsm and the parts of grammar were taken from
http://quut.com/c/ANSI-C-grammar-l-2011.html and extended to support binary
integer constants which are a popular GCC extension.

Reported by: bde