clang_15: mark hardeningUnsupportedFlags fortify3

Port of 74ea4fe24fb ("llvm*Packages.clang: mark
hardeningUnsupportedFlags fortify3").

Changed files
+2 -1
pkgs
development
compilers
llvm
15
clang
+2 -1
pkgs/development/compilers/llvm/15/clang/default.nix
···
'';
passthru = {
+
inherit libllvm;
isClang = true;
-
inherit libllvm;
+
hardeningUnsupportedFlags = [ "fortify3" ];
};
meta = llvm_meta // {