Deprecated functions with lyx-2.3.7dev

[Jean-Pierre Chrétien]

Dear developers,

I recompiled lyx-2.3.7dev to cope with the problem of hunspell library missing 
with Debian bookstorm, and I got a bunch of warnings about std:unary and 
std:binary deprecated functions declared in in stl_function.h.
There ois also one similar warning about mem_fun_ref.

<cite>
../../2.3.x/src/TextClass.cpp:75:33: warning: ‘template<class _Arg, class 
_Result> struct std::unary_function’ is deprecated [-Wdeprecated-declarations]
    75 | class LayoutNamesEqual : public unary_function<Layout, bool> {
       |                                 ^~~~~~~~~~~~~~
In file included from /usr/include/c++/12/string:48,
                  from ../../2.3.x/src/support/strfwd.h:42,
                  from ../../2.3.x/src/support/docstring.h:16,
                  from ../../2.3.x/src/Citation.h:15,
                  from ../../2.3.x/src/TextClass.h:13,
                  from ../../2.3.x/src/TextClass.cpp:17:
/usr/include/c++/12/bits/stl_function.h:117:12: note: declared here
   117 |     struct unary_function
</cite>

Configuration
   Host type:               x86_64-pc-linux-gnu
   Special build flags:      build=development std-regex warnings assertions 
stdlib-debug use-hunspell use-enchant
   Bundled libraries:        boost hunspell
   C++ Compiler:            g++ (12.2.0)
   C++ Compiler flags:       -Wall -Wextra -fPIC -g -O -std=c++14 
-Wno-deprecated-copy
   C++ Compiler user flags:
   Linker flags:
   Linker user flags:
   Qt Frontend:
       Qt version:	   5.15.8
   Packaging:               posix
   LyX binary dir:          /usr/local/bin
   LyX files dir:           /usr/local/share/lyx

on Debian bookworm.

-- 
Jean-Pierre