[sanitizer] Handle Gentoo's libstdc++ path

On Gentoo, libc++ is indeed in /usr/include/c++/*, but libstdc++ is at
e.g. /usr/lib/gcc/x86_64-pc-linux-gnu/14/include/g++-v14.

Use '/include/g++' as it should be unique enough. Note that the omission of
a trailing slash is intentional to match g++-*.

See llvm#78534 (comment).

Reviewed by: mgorny
Closes: llvm#79264

Signed-off-by: Sam James <sam@gentoo.org>
(cherry picked from commit e8f882f)

compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_report.cpp

@@ -34,8 +34,10 @@ static bool FrameIsInternal(const SymbolizedStack *frame) {
     return true;
   const char *file = frame->info.file;
   const char *module = frame->info.module;
+  // On Gentoo, the path is g++-*, so there's *not* a missing /.
   if (file && (internal_strstr(file, "/compiler-rt/lib/") ||
-               internal_strstr(file, "/include/c++/")))
+               internal_strstr(file, "/include/c++/") ||
+               internal_strstr(file, "/include/g++")))
     return true;
   if (module && (internal_strstr(module, "libclang_rt.")))
     return true;