devel/build2: fix build with libc++ >= 20HEADmain

With libc++ 20 or higher devel/build2 fails to build, with errors
similar to:

    In file included from libbuild2/utility.cxx:27:
    ./libbuild2/script/regex.hxx:620:10: error: 'make_unsigned' cannot be specialized: Users are not allowed to specialize this standard library entity [-Winvalid-specialization]
      620 |   struct make_unsigned<build2::script::regex::line_char>
          |          ^
    /usr/include/c++/v1/__type_traits/make_unsigned.h:75:8: note: marked '_Clang::no_specializations' here
       75 | struct _LIBCPP_NO_SPECIALIZATIONS make_unsigned {
          |        ^
    /usr/include/c++/v1/__config:1167:9: note: expanded from macro '_LIBCPP_NO_SPECIALIZATIONS'

Upstream committed a fix for this in
https://github.com/build2/build2/commit/7cf9cec, so add that as a patch
file.

PR:		292867
Approved by:	fuz (maintainer)
MFH:		2026Q1

0 files changed, 0 insertions, 0 deletions