gn build: unbreak mac (and maybe win) after r351258, r351277

The check-hwasan build files assert that current_os == "linux" || current_os ==
"android", so pull it in only there.

ar is unused on mac, so don't set it in the stage2 toolchain. (It'd be nicer to
use llvm-libtool on mac instead of host libtool, but llvm-libtool doesn't seem
to understand the -no_warning_for_no_symbols flag.)

Differential Revision: https://reviews.llvm.org/D56898

llvm-svn: 351519

utils/gn/build/toolchain/BUILD.gn

@@ -157,13 +157,17 @@ template("stage2_unix_toolchain") {
     cc = "bin/clang"
     cxx = "bin/clang++"
     ld = cxx
-    ar = "bin/llvm-ar"
+    if (current_os != "mac") {
+      ar = "bin/llvm-ar"
+    }
 
     deps = [
       "//:clang($host_toolchain)",
       "//:lld($host_toolchain)",
-      "//:llvm-ar($host_toolchain)",
     ]
+    if (current_os != "mac") {
+      deps += [ "//:llvm-ar($host_toolchain)" ]
+    }
   }
 }
 

utils/gn/secondary/BUILD.gn

@@ -5,10 +5,12 @@ import("//llvm/utils/gn/build/toolchain/compiler.gni")
 group("default") {
   deps = [
     "//clang/test",
-    "//compiler-rt/test/hwasan",
     "//lld/test",
     "//llvm/test",
   ]
+  if (current_os == "linux" || current_os == "android") {
+    deps += [ "//compiler-rt/test/hwasan" ]
+  }
 
   testonly = true
 }