gn build: color linker errors when using lld

llvm-svn: 369951

utils/gn/build/BUILD.gn

@@ -42,6 +42,9 @@ config("compiler_defaults") {
       cflags += [ "-O3" ]
     }
     cflags += [ "-fdiagnostics-color" ]
+    if (use_lld) {
+      ldflags += [ "-Wl,--color-diagnostics" ]
+    }
     cflags_cc = [
       "-std=c++14",
       "-fvisibility-inlines-hidden",