* lisp/progmodes/hideif.el: update for new C++ standards and extensions

* lisp/progmodes/hideif.el: update for new C++ standards and extensions

Matching gcc/clang behavior on stringification including keeping the same
number of white spaces.  C++11, C++14, C++17 and GCC literals extension are
supported.  Preprocessing time floating point operation supported but limited
to Emacs internal representation which is C data type "double".  Also support
some frequently used keywords like __LINE__, __TIME__, __DATE__ and so on.

(hif-clear-all-ifdef-defined, hif-show-all, hif-after-revert-function)
(hide-ifdef-define, hide-ifdefs, show-ifdefs): interactive behavior changes,
mainly to allow operation within the marked region.
(hif-eval, hif-__LINE__, hif-__FILE__, hif-__COUNTER__, hif-__cplusplus)
(hif-__DATE__, hif-__TIME__, hif-__STDC__, hif-__STDC_VERSION__)
(hif-__STDC_HOST__, hif-__FILE__, hif-full-match, hif-is-number, hif-is-float)
(hif-delete-char-in-string, hif-string-to-decfloat, hif-string-to-hexfloat)
(hif-strtok, hif-is-white, hif-backward-comment, hif-split-signed-token)
(hif-keep-single, hif-display-macro): new functions.
(hide-ifdef-verbose, hide-ifdef-evalulate-enter-hook)
(hide-ifdef-evalulate-leave-hook, hide-ifdef-evaluator, hif-predefine-alist)
(hif-numtype-suffix-regexp, hif-bin-regexp, hif-hex-regexp, hif-oct-regexp)
(hif-dec-regexp, hif-decfloat-regexp, hif-hexfloat-regexp)
(hif-unicode-prefix-regexp, hif-verbose-define-count): new constants or
variables.
(hif-macroref-regexp, hif-token-alist, hif-token-regexp)
(hif-string-literal-regexp): modified constants for faster regexp processing.
(hide-ifdef-expand-reinclusion-guard): renamed from
`hide-ifdef-expand-reinclusion-protection' to match commonly used term.
(hif-lookup, hif-defined, hif-string-to-number, hif-tokenize, hif-nextoken)
(hif-if-valid-identifier-p, hif-define-operator, hif-expand-token-list)
(hif-parse-exp, hif-math, hif-factor, hif-get-argument-list, hif-stringify)
(hif-token-concat, hif-mathify, hif-comma, hif-token-stringification)
(hif-token-concatenation, hif-macro-supply-arguments, hif-evaluate-macro)
(hif-find-define, hif-add-new-defines, hide-ifdef-guts, hif-undefine-symbol)
(hide-ifdef-set-define-alist, hide-ifdef-use-define-alist): modified functions
for new internal data representation, mainly for stringification and white
space preservation.  Also better error handling to report source line number
and more informative error messages.