llvmPackages_{12,13,14,15,16,17,git}.{libcxx,libcxxabi}: merge libcxxabi into libcxx (#292043)

- merge libcxxabi into libcxx for LLVM 12, 13, 14, 15, 16, 17, and git.
- remove the link time workaround `-lc++ -lc++abi` from 58 packages as it is no longer required.
- fixes https://github.com/NixOS/nixpkgs/issues/166205
- provides alternative fixes for. https://github.com/NixOS/nixpkgs/issues/269548 https://github.com/NixOS/nix/issues/9640
- pkgsCross.x86_64-freebsd builds work again

This change can be represented in 3 stages
1. merge libcxxabi into libcxx -- files: pkgs/development/compilers/llvm/[12, git]/{libcxx, libcxxabi}
2. update stdenv to account for merge -- files: stdenv.{adapters, cc.wrapper, darwin}
3. remove all references to libcxxabi outside of llvm (about 58 packages modified)

### merging libcxxabi into libcxx
- take the union of the libcxxabi and libcxx cmake flags
- eliminate the libcxx-headers-only package - it was only needed to break libcxx <-> libcxxabi circular dependency
- libcxx.cxxabi is removed. external cxxabi (freebsd) will symlink headers / libs into libcxx.
- darwin will re-export the libcxxabi symbols into libcxx so linking `-lc++` is sufficient.
- linux/freebsd `libc++.so` is a linker script `LINK(libc++.so.1, -lc++abi)` making `-lc++` sufficient.
- libcxx/default.nix [12, 17] are identical except for patches and `LIBCXX_ADDITIONAL_LIBRARIES` (only used in 16+)
- git/libcxx/defaul.nix  does not link with -nostdlib when useLLVM is true so flag is removed. this is not much different than before as libcxxabi used -nostdlib where libcxx did not, so libc was linked in anyway.

### stdenv changes
- darwin bootstrap, remove references to libcxxabi and cxxabi
- cc-wrapper: remove c++ link workaround when libcxx.cxxabi doesn't exist (still exists for LLVM pre 12)
- adapter: update overrideLibcxx to account for a pkgs.stdenv that only has libcxx

### 58 package updates
- remove `NIX_LDFLAGS = "-l${stdenv.cc.libcxx.cxxabi.libName}` as no longer needed
- swift, nodejs_v8 remove libcxxabi references in the clang override

https://github.com/NixOS/nixpkgs/pull/292043

6 files changed, 1 insertions, 30 deletions

diff --git a/pkgs/by-name/as/ast-grep/package.nix b/pkgs/by-name/as/ast-grep/package.nix
index c0fa05e30c167..1f952c0306402 100644
--- a/pkgs/by-name/as/ast-grep/package.nix
+++ b/pkgs/by-name/as/ast-grep/package.nix
@@ -18,11 +18,6 @@ rustPlatform.buildRustPackage rec {
 
   cargoHash = "sha256-48ZVbRJkpMO+kJE5Kz96McjXhMtu4TzzjfyYdggNWkQ=";
 
-  # Work around https://github.com/NixOS/nixpkgs/issues/166205.
-  env = lib.optionalAttrs stdenv.cc.isClang {
-    NIX_LDFLAGS = "-l${stdenv.cc.libcxx.cxxabi.libName}";
-  };
-
   nativeBuildInputs = [ installShellFiles ];
 
   # error: linker `aarch64-linux-gnu-gcc` not found
diff --git a/pkgs/by-name/gc/gcs/package.nix b/pkgs/by-name/gc/gcs/package.nix
index 3ded7802d6746..406db2018624b 100644
--- a/pkgs/by-name/gc/gcs/package.nix
+++ b/pkgs/by-name/gc/gcs/package.nix
@@ -59,11 +59,6 @@ buildGoModule rec {
   flags = [ "-a -trimpath" ];
   ldflags = [ "-s" "-w" "-X github.com/richardwilkes/toolbox/cmdline.AppVersion=${version}" ];
 
-  # Workaround for https://github.com/NixOS/nixpkgs/issues/166205
-  env = lib.optionalAttrs (stdenv.cc.libcxx != null) {
-    NIX_LDFLAGS = "-l${stdenv.cc.libcxx.cxxabi.libName}";
-  };
-
   installPhase = ''
     runHook preInstall
     install -Dm755 $GOPATH/bin/gcs -t $out/bin
diff --git a/pkgs/by-name/ni/nickel/package.nix b/pkgs/by-name/ni/nickel/package.nix
index 76ba075b5a046..612392e91ba28 100644
--- a/pkgs/by-name/ni/nickel/package.nix
+++ b/pkgs/by-name/ni/nickel/package.nix
@@ -36,11 +36,6 @@ rustPlatform.buildRustPackage rec {
 
   cargoBuildFlags = [ "-p nickel-lang-cli" "-p nickel-lang-lsp" ];
 
-  env = lib.optionalAttrs stdenv.cc.isClang {
-    # Work around https://github.com/NixOS/nixpkgs/issues/166205.
-    NIX_LDFLAGS = "-l${stdenv.cc.libcxx.cxxabi.libName}";
-  };
-
   nativeBuildInputs = [
     python3
   ];
diff --git a/pkgs/by-name/sy/symbolicator/package.nix b/pkgs/by-name/sy/symbolicator/package.nix
index ebec2b81a6d8a..20ee664e2cd1a 100644
--- a/pkgs/by-name/sy/symbolicator/package.nix
+++ b/pkgs/by-name/sy/symbolicator/package.nix
@@ -47,9 +47,6 @@ rustPlatform.buildRustPackage rec {
     SYMBOLICATOR_GIT_VERSION = src.rev;
     SYMBOLICATOR_RELEASE = version;
     ZSTD_SYS_USE_PKG_CONFIG = true;
-  } // lib.optionalAttrs stdenv.cc.isClang {
-    # Work around https://github.com/NixOS/nixpkgs/issues/166205.
-    NIX_LDFLAGS = "-l${stdenv.cc.libcxx.cxxabi.libName}";
   };
 
   # tests require network access
diff --git a/pkgs/by-name/ta/tabby/package.nix b/pkgs/by-name/ta/tabby/package.nix
index fa52d372ab9a8..5806d60077f58 100644
--- a/pkgs/by-name/ta/tabby/package.nix
+++ b/pkgs/by-name/ta/tabby/package.nix
@@ -97,8 +97,6 @@ let
   cudaBuildInputs = [ llamaccpPackage ];
   rocmBuildInputs = [ llamaccpPackage ];
 
-  LLAMA_CPP_LIB = "${llamaccpPackage.outPath}/lib";
-
 in
 rustPlatform.buildRustPackage {
   inherit pname version;
@@ -148,11 +146,7 @@ rustPlatform.buildRustPackage {
   ++ optionals enableRocm rocmBuildInputs
   ;
 
-  env = lib.mergeAttrsList [
-    { inherit LLAMA_CPP_LIB; }
-    # Work around https://github.com/NixOS/nixpkgs/issues/166205
-    (lib.optionalAttrs stdenv.cc.isClang { NIX_LDFLAGS = "-l${stdenv.cc.libcxx.cxxabi.libName}"; })
-  ];
+  env.LLAMA_CPP_LIB = "${lib.getLib llamaccpPackage}/lib";
   patches = [ ./0001-nix-build-use-nix-native-llama-cpp-package.patch ];
 
   # Fails with:
diff --git a/pkgs/by-name/us/usql/package.nix b/pkgs/by-name/us/usql/package.nix
index 7c0b093dfffc8..21a5bc99e67ba 100644
--- a/pkgs/by-name/us/usql/package.nix
+++ b/pkgs/by-name/us/usql/package.nix
@@ -50,11 +50,6 @@ buildGoModule rec {
     "no_adodb"
   ];
 
-  # Work around https://github.com/NixOS/nixpkgs/issues/166205.
-  env = lib.optionalAttrs stdenv.cc.isClang {
-    NIX_LDFLAGS = "-l${stdenv.cc.libcxx.cxxabi.libName}";
-  };
-
   ldflags = [
     "-s"
     "-w"