Un-nest configs in GN files.

third_party/lzma_sdk/BUILD.gn

Index: third_party/lzma_sdk/BUILD.gn
diff --git a/third_party/lzma_sdk/BUILD.gn b/third_party/lzma_sdk/BUILD.gn
index 2afe7b4f7e307c1c0d82c0591a748184a16f4f17..1f36abdb59d59bb455e2134c1dfcc709c83bc178 100644
--- a/third_party/lzma_sdk/BUILD.gn
+++ b/third_party/lzma_sdk/BUILD.gn
@@ -6,6 +6,15 @@ config("lzma_sdk_config") {
   include_dirs = [ "." ]
 }
 
+# Must be in a config because of how GN orders flags (otherwise -Wall will
+# appear after this, and turn it back on).
+config("clang_warnings") {
+  if (is_clang) {
+    # Upstream uses self-assignment to avoid warnings.
+    cflags = [ "-Wno-self-assign" ]
+  }
+}
+
 static_library("lzma_sdk") {
   sources = [
     "7z.h",
@@ -50,17 +59,11 @@ static_library("lzma_sdk") {
   ]
 
   configs -= [ "//build/config/compiler:chromium_code" ]
-  configs += [ "//build/config/compiler:no_chromium_code" ]
+  configs += [
+    "//build/config/compiler:no_chromium_code",
 
+    # Must be after no_chromium_code for warning flags to be ordered correctly.
+    ":clang_warnings",
+  ]
   public_configs = [ ":lzma_sdk_config" ]
-
-  # Must be in a config because of how GN orders flags (otherwise -Wall will
-  # appear after this, and turn it back on).
-  config("clang_warnings") {
-    if (is_clang) {
-      # Upstream uses self-assignment to avoid warnings.
-      cflags = [ "-Wno-self-assign" ]
-    }
-  }
-  configs += [ ":clang_warnings" ]
 }