devel/llvm13: fix build with clang 21
Recent versions of clang complain about explicit copy constructors,
leading to errors similar to:
In file included from /wrkdirs/usr/ports/devel/llvm13/work/llvm-project-13.0.1.src/llvm/tools/sancov/sancov.cpp:16:
In file included from /wrkdirs/usr/ports/devel/llvm13/work/llvm-project-13.0.1.src/llvm/include/llvm/MC/MCContext.h:12:
/wrkdirs/usr/ports/devel/llvm13/work/llvm-project-13.0.1.src/llvm/include/llvm/ADT/DenseMap.h:128:16: warning: variable 'NumEntries' set but not used [-Wunused-but-set-variable]
128 | unsigned NumEntries = getNumEntries();
| ^
/wrkdirs/usr/ports/devel/llvm13/work/llvm-project-13.0.1.src/llvm/tools/sancov/sancov.cpp:512:42: error: chosen constructor is explicit in copy-initialization
512 | return SpecialCaseList::createOrDie({{ClBlacklist}},
| ^~~~~~~~~~~~~
/usr/include/c++/v1/string:1153:64: note: explicit constructor declared here
1153 | _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 explicit basic_string(const _Tp& __t) {
| ^
/usr/include/c++/v1/__vector/vector.h:276:91: note: passing argument to parameter '__il' here
276 | _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI vector(initializer_list<value_type> __il) {
| ^In this case, ClBlacklist is an instance of cl::opt, not a
std::string as expected. Use getValue() to get the actual
std::string value.
PR: 292109
Approved by: brooks (maintainer)
MFH: 2026Q1
(cherry picked from commit d3097136efd1edc01760f7659ff6c9ded2594d96)