feat: add //lib:enable_runfiles config_setting (#807)

diff --git a/lib/BUILD.bazel b/lib/BUILD.bazel
index a9c0afc..b03d809 100644
--- a/lib/BUILD.bazel
+++ b/lib/BUILD.bazel
@@ -31,6 +31,11 @@
     build_setting_default = True if is_bzlmod_enabled() else False,
 )
 
+config_setting(
+    name = "enable_runfiles",
+    values = {"enable_runfiles": "true"},
+)
+
 toolchain_type(
     name = "jq_toolchain_type",
 )