Use proper clang plugin name in GN build.

This uses the proper name of the Clang plugin on Linux (previously it was hardcoded to the Mac-style name).

This also fixes the path naming so the clang plugin is correct no matter where the output directory is.

R=thakis@chromium.org

Review URL: https://codereview.chromium.org/121423002

git-svn-id: http://src.chromium.org/svn/trunk/src/build@242573 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

config/clang/BUILD.gn

@@ -6,12 +6,19 @@ config("find_bad_constructs") {
   cflags = [
     "-Xclang", "-load",
     "-Xclang",
+  ]
 
-    # TODO(brettw) express this in terms of a relative dir from the output.
-    # for now, assume the output dir is two levels deep under the source
-    # (like "out/Debug").
-    "../../third_party/llvm-build/Release+Asserts/lib/libFindBadConstructs.dylib",
+  if (is_mac) {
+    cflags += rebase_path(
+      "//third_party/llvm-build/Release+Asserts/lib/libFindBadConstructs.dylib",
+      ".", root_build_dir)
+  } else if (is_linux) {
+    cflags += rebase_path(
+      "//third_party/llvm-build/Release+Asserts/lib/libFindBadConstructs.so",
+      ".", root_build_dir)
+  }
 
+  cflags += [
     "-Xclang", "-add-plugin",
     "-Xclang", "find-bad-constructs",
   ]