jsoncpp: Disable libcxx module

This is to unblock module build in jsoncpp.

Bug: 428778692
Change-Id: I43366ba435501d8b242d5892016dc1a6146b5e54
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6768662
Reviewed-by: Nico Weber <thakis@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>
Auto-Submit: Takuto Ikuta <tikuta@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1490751}
NOKEYCHECK=True
GitOrigin-RevId: 24df863d661ad5edb5074821f7c9d8843169ca1e
diff --git a/BUILD.gn b/BUILD.gn
index 822bc39..3d21670 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -41,6 +41,10 @@
 
   # jsoncpp makes use of static objects for things like a null singleton.
   configs += [ "//build/config/compiler:no_exit_time_destructors" ]
+
+  # TODO(https://github.com/open-source-parsers/jsoncpp/pull/1612): Remove this
+  # when the PR is merged.
+  use_libcxx_modules = false
 }
 
 if (build_with_chromium) {