init

This builds a very basic version of the nats.c client (no TLS, no
streaming/jetstream/whatever, since those bring in complex
dependencies and I do not need them at the moment). Right now it
contains a simple test program that demonstrates the functionality
(cool!), but the plan is for the nats.zig to bind the API into a
nicer, zig-like shape and re-export it. Then this becomes a package.
The current function could become a test, though it's a bit complex
for a unit test (and requires connecting to an externally-running NATS
server in order to work).

build.zig

@@ -0,0 +1,46 @@
+const std = @import("std");
+const nats_build = @import("./nats-c.build.zig");
+
+pub fn build(b: *std.Build) void {
+    const target = b.standardTargetOptions(.{});
+    const optimize = b.standardOptimizeOption(.{});
+
+    // const nats = b.addModule("nats", .{
+    //     .source_file = .{ .path = "source/nats.zig" },
+    // });
+
+    const nats = b.addExecutable(.{
+        .name = "nats_test",
+        .root_source_file = .{ .path = "src/nats.zig" },
+        .target = target,
+        .optimize = optimize,
+    });
+
+    const tinfo = nats.target_info.target;
+
+    const nats_c = nats_build.nats_c_lib(
+        b,
+        .{ .name = "nats-c", .target = target, .optimize = optimize },
+    );
+    switch (tinfo.os.tag) {
+        .windows => {
+            if (tinfo.abi != .msvc) {
+                nats_c.addCSourceFiles(&.{"src/win-crosshack.c"}, &.{"-fno-sanitize=undefined"});
+            }
+        },
+        else => {},
+    }
+
+    nats.linkLibrary(nats_c);
+    b.installArtifact(nats);
+
+    const main_tests = b.addTest(.{
+        .root_source_file = .{ .path = "src/nats.zig" },
+        .target = target,
+        .optimize = optimize,
+    });
+
+    const run_main_tests = b.addRunArtifact(main_tests);
+    const test_step = b.step("test", "Run tests");
+    test_step.dependOn(&run_main_tests.step);
+}