Un-nest configs in GN files.

third_party/yasm/BUILD.gn

Index: third_party/yasm/BUILD.gn
diff --git a/third_party/yasm/BUILD.gn b/third_party/yasm/BUILD.gn
index fcb779ac82b04ba7c2e85a75b4e869f746b9bddc..b301a10b8b0b4679cf58520bd156abcac1c439f7 100644
--- a/third_party/yasm/BUILD.gn
+++ b/third_party/yasm/BUILD.gn
@@ -135,6 +135,20 @@ if (current_toolchain == host_toolchain) {
     ]
   }
 
+  config("re2c_warnings") {
+    # re2c is missing CLOSEVOP from one switch.
+    if (is_clang) {
+      cflags = [
+        # re2c is missing CLOSEVOP from one switch.
+        "-Wno-switch",
+
+        # re2c contains many static functions in headers (because it's
+        # a C library predating C99.)
+        "-Wno-unused-function",
+      ]
+    }
+  }
+
   executable("re2c") {
     sources = [
       "source/patched-yasm/tools/re2c/actions.c",
@@ -148,30 +162,26 @@ if (current_toolchain == host_toolchain) {
       "source/patched-yasm/tools/re2c/translate.c",
     ]
 
-    config("re2c_warnings") {
-      # re2c is missing CLOSEVOP from one switch.
-      if (is_clang) {
-        cflags = [
-          # re2c is missing CLOSEVOP from one switch.
-          "-Wno-switch",
-
-          # re2c contains many static functions in headers (because it's
-          # a C library predating C99.)
-          "-Wno-unused-function",
-        ]
-      }
-    }
     configs -= [ "//build/config/compiler:chromium_code" ]
     configs += [
+      ":re2c_warnings",
       ":yasm_config",
       "//build/config/compiler:no_chromium_code",
-      ":re2c_warnings",
     ]
     deps = [
       "//build/config/sanitizers:deps",
     ]
   }
 
+  config("yasm_warnings") {
+    if (is_clang) {
+      cflags = [
+        # reg3264type in x86expr.c is unused.
+        "-Wno-unused-local-typedef",
+      ]
+    }
+  }
+
   executable("yasm") {
     sources = [
       "source/patched-yasm/frontends/yasm/yasm-options.c",
@@ -258,20 +268,11 @@ if (current_toolchain == host_toolchain) {
     configs -= [ "//build/config/compiler:chromium_code" ]
     configs += [
       ":yasm_config",
+      ":yasm_warnings",
       "//build/config/compiler:no_chromium_code",
       "//build/config/compiler:no_incompatible_pointer_warnings",
     ]
 
-    config("yasm_warnings") {
-      if (is_clang) {
-        cflags = [
-          # reg3264type in x86expr.c is unused.
-          "-Wno-unused-local-typedef",
-        ]
-      }
-    }
-    configs += [ ":yasm_warnings" ]
-
     # Yasm generates a bunch of .c files which its source file #include.
     # Add the |target_gen_dir| into the include path so it can find them.
     # Ideally, these generated .c files would be placed into a separate