add(timestamp): timestamp build configuration option to add timestamps before log messages

build.zig

@@ -4,6 +4,14 @@ const std = @import("std");
 // declaratively construct a build graph that will be executed by an external
 // runner.
 pub fn build(b: *std.Build) void {
+    // build options to customize the log message formating
+    const include_timestamp = b.option(bool, "timestamp", "Enable inclusion of timestamps in log messages (default: true)") orelse true;
+
+    const options = b.addOptions();
+    options.addOption(bool, "timestamp", include_timestamp);
+
+    const options_module = options.createModule();
+
     // Standard target options allows the person running `zig build` to choose
     // what target to build for. Here we do not override the defaults, which
     // means any target is allowed, and the default is native. Other options
@@ -21,7 +29,9 @@ pub fn build(b: *std.Build) void {
         .root_source_file = b.path("src/zlog.zig"),
         .target = target,
         .optimize = optimize,
+        .link_libc = include_timestamp, // uses c std library <time.h>
     });
+    zlog_module.addImport("build_options", options_module);
 
     const exe = b.addExecutable(.{
         .name = "zlog",