add zig 0.9.0

runtimes/default.nix

@@ -14,4 +14,5 @@ args: {
     "erlang" = import ./erlang.nix args;
     "gawk-awk" = import ./gawk-awk.nix args;
     "openjdk11_headless-java" = import ./openjdk11_headless-java.nix args;
+    "zig" = import ./zig.nix args;
 }

runtimes/zig.nix

@@ -0,0 +1,43 @@
+{pkgs, piston, ...}:
+let
+    pkg = pkgs.zig;
+in piston.mkRuntime {
+    language = "zig";
+    version = pkg.version;
+    aliases = [];
+
+    # Add .zig extension for compile script and optimize compiler for small programs
+    compile = ''
+        rename 's/$/\.zig/' "$@"
+        ${pkg}/bin/zig build-exe -O ReleaseSafe --color off --cache-dir . --global-cache-dir . --name out *.zig
+    '';
+
+    # Remove first arg filename and run binary with remaining args
+    run = ''
+        shift
+        ./out "$@"
+    '';
+
+    # These should output "OK" to STDOUT if everything looks good
+    # Run the following command to test the package:
+    # $ ./piston test zig
+    tests = [
+        # Standard output test
+        (piston.mkTest {
+            files = {
+                "test.zig" = ''
+                    const std = @import("std");
+
+                    pub fn main() !void {
+                        const stdout = std.io.getStdOut().writer();
+                        try stdout.print("OK\n", .{});
+                    }
+                '';
+            };
+            args = [];
+            stdin = "";
+            packages = [];
+            main = "test.zig";
+        })
+    ];
+}