core: add tests for ghostty.h

* ensure that `ghostty.h` compiles during basic Zig tests
* ensure that non-exhaustive enums are kept synchronized between
  `ghostty.h` and their respective Zig counterpart.
* adjust some enums that varied from established conventions

src/lib/enum.zig

@@ -91,3 +91,55 @@ test "abi by removing a key" {
         try testing.expectEqual(2, @intFromEnum(T.d));
     }
 }
+
+/// Verify that for every key in enum T, there is a matching declaration in
+/// `ghostty.h` with the correct value.
+pub fn checkGhosttyHEnum(comptime T: type, comptime prefix: []const u8) !void {
+    const info = @typeInfo(T);
+
+    try std.testing.expect(info == .@"enum");
+    try std.testing.expect(info.@"enum".tag_type == c_int);
+
+    @setEvalBranchQuota(1000000);
+
+    const c = @cImport({
+        @cInclude("ghostty.h");
+    });
+
+    var set: std.EnumSet(T) = .initFull();
+
+    const c_decls = @typeInfo(c).@"struct".decls;
+    const enum_fields = info.@"enum".fields;
+
+    inline for (enum_fields) |field| {
+        const upper_name = comptime u: {
+            var buf: [128]u8 = undefined;
+            break :u std.ascii.upperString(&buf, field.name);
+        };
+
+        inline for (c_decls) |decl| {
+            if (!comptime std.mem.startsWith(u8, decl.name, prefix)) continue;
+
+            const suffix = decl.name[prefix.len..];
+
+            if (!comptime std.mem.eql(u8, suffix, upper_name)) continue;
+
+            std.testing.expectEqual(field.value, @field(c, decl.name)) catch |e| {
+                std.log.err(@typeName(T) ++ " key " ++ field.name ++ " does not have the same backing int as " ++ decl.name, .{});
+                return e;
+            };
+
+            set.remove(@enumFromInt(field.value));
+        }
+    }
+
+    std.testing.expect(set.count() == 0) catch |e| {
+        var it = set.iterator();
+        while (it.next()) |v| {
+            var buf: [128]u8 = undefined;
+            const n = std.ascii.upperString(&buf, @tagName(v));
+            std.log.err("ghostty.h is missing value for {s}{s}, {t}", .{ prefix, n, v });
+        }
+        return e;
+    };
+}