compiler, testing: Build System for Compilation

The compilation code was written as a precursor for implementation
with macros. The updates in this commit make the switch.

There is still plenty to do:

1. Comment Walker.
2. Comment Macros.

Signed-off-by: Will Hawkins <hawkinsw@obs.cr>

Tests/p4rseTests/SupportTests/Macros.swift

@@ -0,0 +1,51 @@
+// p4rse, Copyright 2026, Will Hawkins
+//
+// This file is part of p4rse.
+//
+// This file is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+import Common
+import Foundation
+import Macros
+import P4Lang
+import P4Runtime
+import SwiftTreeSitter
+import Testing
+import TreeSitter
+import TreeSitterP4
+
+@testable import Macros
+
+func wrapper_test_mustor() -> Int {
+    let x: Int? = 2
+    var i = 0
+    #MustOr(result: i, thing: x, or: 1)
+    return i
+}
+
+func wrapper_test_mustor_none() -> Int {
+    let x: Int? = .none
+    var i = 0
+    #MustOr(result: i, thing: x, or: 1)
+    return i
+}
+
+
+@Test func test_mustor() async throws {
+    #expect(wrapper_test_mustor() == 2)
+}
+
+@Test func test_mustor_none() async throws {
+    #expect(wrapper_test_mustor_none() == 1)
+}