MacOS and Library support

[rjkroege]

This PR contains a number of changes with two primary goals:

• Support macos build hosts for macos and linux targets.
• Compile Go libraries and use them for Zig linkage

Example of Library

Fragment from the build.zig

    // Create a Zig executable that calls Go code.
    const driver_exe = b.addExecutable(.{
        .name = "zigcallsgo",
        .root_source_file = b.path("src/main.zig"),
        .target = target,
        .optimize = optimize,
    });

    // Build the Go library from package in `go-lib`.
    const go_lib = go.addLibrary(b, .{
        .name = "libhtmlescaper.a",
        .target = target,
        .optimize = optimize,
        .package_path = b.path("go-lib"),
    });

    driver_exe.addIncludePath(go_lib.getIncludePath());
    driver_exe.addObjectFile(go_lib.getEmittedBin());
    // NB: Go runtime requires arm-linux-gnueabihf to not crash on arm target.
    driver_exe.linkLibC();

Changes

• Changes to build for 0.14
• Sufficient for building a simple Go program
• Changes for CGO support on MacOS
• Support building Go libraries
• Restore static linking support
• Fixed a typo