Add support for Bazel build system (#1275)

Co-authored-by: Christopher Dunn <cdunn2001@gmail.com>

Author: mglb

BUILD.bazel

@@ -0,0 +1,37 @@
+licenses(["unencumbered"])  # Public Domain or MIT
+
+exports_files(["LICENSE"])
+
+cc_library(
+    name = "jsoncpp",
+    srcs = [
+        "src/lib_json/json_reader.cpp",
+        "src/lib_json/json_tool.h",
+        "src/lib_json/json_value.cpp",
+        "src/lib_json/json_writer.cpp",
+    ],
+    hdrs = [
+        "include/json/allocator.h",
+        "include/json/assertions.h",
+        "include/json/config.h",
+        "include/json/json_features.h",
+        "include/json/forwards.h",
+        "include/json/json.h",
+        "include/json/reader.h",
+        "include/json/value.h",
+        "include/json/version.h",
+        "include/json/writer.h",
+    ],
+    copts = [
+        "-DJSON_USE_EXCEPTION=0",
+        "-DJSON_HAS_INT64",
+    ],
+    includes = ["include"],
+    visibility = ["//visibility:public"],
+    deps = [":private"],
+)
+
+cc_library(
+    name = "private",
+    textual_hdrs = ["src/lib_json/json_valueiterator.inl"],
+)