git: ca0ca0a01359 - main - devel/build2: fix build with libc++ >= 20

The branch main has been updated by dim:

URL: https://cgit.FreeBSD.org/ports/commit/?id=ca0ca0a01359fe5acccf5a21c4acd2ceceefbd7a

commit ca0ca0a01359fe5acccf5a21c4acd2ceceefbd7a
Author:     Dimitry Andric <dim@FreeBSD.org>
AuthorDate: 2026-02-01 19:17:16 +0000
Commit:     Dimitry Andric <dim@FreeBSD.org>
CommitDate: 2026-02-01 19:54:59 +0000

    devel/build2: fix build with libc++ >= 20
    
    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
---
 .../files/patch-build2_libbuild2_script_regex.hxx     | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/devel/build2/files/patch-build2_libbuild2_script_regex.hxx b/devel/build2/files/patch-build2_libbuild2_script_regex.hxx
new file mode 100644
index 000000000000..11abe3d274c0
--- /dev/null
+++ b/devel/build2/files/patch-build2_libbuild2_script_regex.hxx
@@ -0,0 +1,19 @@
+--- build2/libbuild2/script/regex.hxx.orig	2022-12-16 05:41:50 UTC
++++ build2/libbuild2/script/regex.hxx
+@@ -616,11 +616,16 @@ namespace std
+   // to use as an index in some internal cache regardless if the cache is used
+   // for this specialization (and the cache is used only if CharT is char).
+   //
++  // Note that starting with libc++ 20 we get -Winvalid-specialization for
++  // this specialization. But luckily it doesn't seem to be necessary.
++  //
++#if !defined(_LIBCPP_VERSION) || _LIBCPP_VERSION < 20000
+   template <>
+   struct make_unsigned<build2::script::regex::line_char>
+   {
+     using type = build2::script::regex::line_char;
+   };
++#endif
+ 
+   // When used with libc++ the linker complains that it can't find
+   // __match_any_but_newline<line_char>::__exec() function. The problem is