systemtap: Fix build with gcc-12

systemtap: Fix build with gcc-12

Backport a patch to fix
| ../git/util.cxx:1766:56: error: 'std::pointer_to_unary_function<_Arg, _Result> std::ptr_fun(_Result (*)(_Arg)) [with _Arg = int; _Result = int]' is deprecated: use 'std::function' instea
d [-Werror=deprecated-declarations]
|  1766 |                        std::not1(std::ptr_fun<int, int>(std::isspace))));
|       |                                  ~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~

Signed-off-by: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit 0b360d12203aafd8bf96433d11221a6ed910a11f)
Signed-off-by: Steve Sakoman <steve@sakoman.com>