Expose JSON_USE_EXCEPTION and JSON_HAS_INT64 as Bazel config flags with defaults that match the existing Bazel build.

Switch //:jsoncpp from using copts ro defines for JSON_USE_EXCEPTION and JSON_HAS_INT64 so that rules that depend on it get the same config.
Make src/test_lib_json/fuzz.cpp respect JSON_USE_EXCEPTION.

Author: bcsgh

BUILD.bazel

@@ -1,7 +1,29 @@
 licenses(["unencumbered"])  # Public Domain or MIT
 
+load("@bazel_skylib//rules:common_settings.bzl", "bool_flag")
+
 exports_files(["LICENSE"])
 
+bool_flag(
+    name = "use_exception",
+    build_setting_default = False,
+)
+
+config_setting(
+    name = "use_exception_cfg",
+    flag_values = {":use_exception": "true"},
+)
+
+bool_flag(
+    name = "has_int64",
+    build_setting_default = True,
+)
+
+config_setting(
+    name = "has_int64_cfg",
+    flag_values = {":has_int64": "true"},
+)
+
 cc_library(
     name = "jsoncpp",
     srcs = [
@@ -22,10 +44,13 @@ cc_library(
         "include/json/version.h",
         "include/json/writer.h",
     ],
-    copts = [
-        "-DJSON_USE_EXCEPTION=0",
-        "-DJSON_HAS_INT64",
-    ],
+    defines = select({
+        ":use_exception_cfg": ["JSON_USE_EXCEPTION=1"],
+        "//conditions:default": ["JSON_USE_EXCEPTION=0"],
+    }) + select({
+        ":has_int64_cfg": ["JSON_HAS_INT64"],
+        "//conditions:default": [],
+    }),
     includes = ["include"],
     visibility = ["//visibility:public"],
     deps = [":private"],

MODULE.bazel

@@ -12,3 +12,8 @@ module(
     version = "1.9.7",
     compatibility_level = 1,
 )
+
+bazel_dep(
+    name = "bazel_skylib",
+    version = "1.7.1",
+)

src/test_lib_json/fuzz.cpp

@@ -11,10 +11,6 @@
 #include <memory>
 #include <string>
 
-namespace Json {
-class Exception;
-}
-
 extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
   Json::CharReaderBuilder builder;
 
@@ -45,10 +41,14 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
 
   Json::Value root;
   const auto data_str = reinterpret_cast<const char*>(data);
+#if JSON_USE_EXCEPTION
   try {
+#endif // JSON_USE_EXCEPTION
     reader->parse(data_str, data_str + size, &root, nullptr);
+#if JSON_USE_EXCEPTION
   } catch (Json::Exception const&) {
   }
+#endif // JSON_USE_EXCEPTION
   // Whether it succeeded or not doesn't matter.
   return 0;
 }