bastion: add freestanding C++ standard library (libcxx)feature/freestanding-libcxx

Header-only implementation of a C++ standard library subset for the
freestanding kernel, using Clang builtins wherever possible. Provides
19 public headers (~35 internal files): type_traits, utility, memory,
algorithm, functional, concepts, array, string_view, span, optional,
expected, variant, tuple, bit, limits, new, initializer_list, cstdint,
cstddef, and source_location.

Integration changes:
- kernel/Makefile: add -Ilib/libcxx/include to include path
- kernel/lib/string.cpp: add memchr and strncmp (needed by string_view)
- kernel/lib/cxxabi.cpp: guard placement new against <new> header conflict
- kernel/include/kernel/kernel.h: Panic() now uses std::source_location
- kernel/core/kernel.cpp: Panic() implementation updated to match

Builds cleanly on both x86_64 and aarch64 with zero new warnings.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

1 files changed, 5 insertions, 5 deletions

diff --git a/kernel/core/kernel.cpp b/kernel/core/kernel.cpp
index c2d1806..e381972 100644
--- a/kernel/core/kernel.cpp
+++ b/kernel/core/kernel.cpp
@@ -262,20 +262,20 @@ const PanicInfo& Kernel::GetPanicInfo() const {
     return panic_info;
 }
 
-[[noreturn]] void Kernel::Panic(const char* msg, const char* file, const char* func, uint32_t line) {
+[[noreturn]] void Kernel::Panic(const char* msg, std::source_location loc) {
     state = KernelState::Panicked;
 
     panic_info.message = msg;
-    panic_info.file    = file;
-    panic_info.line    = line;
-    panic_info.func    = func;
+    panic_info.file    = loc.file_name();
+    panic_info.line    = loc.line();
+    panic_info.func    = loc.function_name();
     panic_info.cpu_id  = 0; // TODO: get actual CPU id when SMP is added
 
     // Print panic banner — kcon may or may not be initialized yet
     kcon::putchar('\n');
     kcon::println("!!! KERNEL PANIC !!!");
     kcon::kprintf("  %s\n", msg);
-    kcon::kprintf("  at %s:%s:%u\n", file, func, line);
+    kcon::kprintf("  at %s:%s:%u\n", loc.file_name(), loc.function_name(), loc.line());
     kcon::putchar('\n');
 
     arch::halt();