Fix iOS build for skpinfo.

Change-Id: Id6f6e20831ad84c35a67dbb47ac9eda3d72650b6
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/419839
Commit-Queue: Ben Wagner <bungeman@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
diff --git a/gn/ios.gni b/gn/ios.gni
index 5da6b6e..9434472 100644
--- a/gn/ios.gni
+++ b/gn/ios.gni
@@ -139,6 +139,9 @@
     }
 
     executable("${app_name}_generate_executable") {
+      if (!defined(configs)) {
+        configs = []
+      }
       forward_variables_from(invoker,
                              "*",
                              [
@@ -147,7 +150,11 @@
                                "is_shared_library",
                                "data_sources",
                                "extra_configs",
+                               "configs",
                              ])
+      if (defined(invoker.configs)) {
+        configs += invoker.configs
+      }
       if (defined(invoker.extra_configs)) {
         configs += invoker.extra_configs
       }