Use SmpAllocator when not in Debug

In our case (lots of C headers), codegen went from ~90s to less than 1s.

Author: steeve

src/main.zig

@@ -1,3 +1,4 @@
+const builtin = @import("builtin");
 const std = @import("std");
 const assert = std.debug.assert;
 const mem = std.mem;
@@ -7,11 +8,14 @@ const Translator = @import("Translator.zig");
 
 const fast_exit = @import("builtin").mode != .Debug;
 
-var general_purpose_allocator: std.heap.GeneralPurposeAllocator(.{}) = .init;
+var debug_allocator: std.heap.DebugAllocator(.{}) = .init;
 
 pub fn main() u8 {
-    const gpa = general_purpose_allocator.allocator();
-    defer _ = general_purpose_allocator.deinit();
+    const gpa = if (builtin.mode == .Debug)
+        debug_allocator.allocator()
+    else
+        std.heap.smp_allocator;
+    defer if (builtin.mode == .Debug) std.debug.assert(debug_allocator.deinit() == .ok);
 
     var arena_instance = std.heap.ArenaAllocator.init(std.heap.page_allocator);
     defer arena_instance.deinit();