Unexplained compile errors such missing "pd_api.h"

[STREGA]

The following errors might be solved with the solution below:

• Could not build Objective-C module 'CPlaydate'
• 'pd_api.h' file not found

The helper variables in Package.swift cannot be immutable when below the let package = declaration.
Change them to computed variables like so:

var gccIncludePrefix: String {
    return "/usr/local/playdate/gcc-arm-none-eabi-9-2019-q4-major/lib/gcc/arm-none-eabi/9.2.1"
}
var playdateSDKPath: String {
    if let env = Context.environment["PLAYDATE_SDK_PATH"] {
        return env
    }
    return "\(Context.environment["HOME"]!)/Developer/PlaydateSDK/"
}
var swiftSettings: [SwiftSetting] {[
    .enableExperimentalFeature("Embedded"),
    .unsafeFlags([
        "-whole-module-optimization",
        "-Xfrontend", "-disable-objc-interop",
        "-Xfrontend", "-disable-stack-protector",
        "-Xfrontend", "-function-sections",
        "-Xfrontend", "-gline-tables-only",
        "-Xcc", "-DTARGET_EXTENSION",
        "-Xcc", "-I", "-Xcc", "\(gccIncludePrefix)/include",
        "-Xcc", "-I", "-Xcc", "\(gccIncludePrefix)/include-fixed",
        "-Xcc", "-I", "-Xcc", "\(gccIncludePrefix)/../../../../arm-none-eabi/include",
        "-I", "\(playdateSDKPath)/C_API"
    ]),
]}

[STREGA]

Fixing this in the Template would be a good idea. If they are always computed variables then users are less likely to change them.

// swift-tools-version: 6.0

import Foundation
import PackageDescription


let package = Package(
    name: "PlaydateKitTemplate",
    platforms: [.macOS(.v14)],
    products: [.library(name: "PlaydateKitTemplate", targets: ["PlaydateKitTemplate"])],
    dependencies: [
        .package(url: "https://github.com/finnvoor/PlaydateKit.git", branch: "main"),
    ],
    targets: [
        .target(
            name: "PlaydateKitTemplate",
            dependencies: [
                .product(name: "PlaydateKit", package: "PlaydateKit")
            ],
            swiftSettings: swiftSettings
        ),
    ],
    swiftLanguageModes: [.v6]
)


// MARK: - Helper Variables
// note: These must be computed variables when beneath the `let package =` declaration.

var swiftSettings: [SwiftSetting] {[
    .enableExperimentalFeature("Embedded"),
    .unsafeFlags([
        "-whole-module-optimization",
        "-Xfrontend", "-disable-objc-interop",
        "-Xfrontend", "-disable-stack-protector",
        "-Xfrontend", "-function-sections",
        "-Xfrontend", "-gline-tables-only",
        "-Xcc", "-DTARGET_EXTENSION",
        "-Xcc", "-I", "-Xcc", "\(gccIncludePrefix)/include",
        "-Xcc", "-I", "-Xcc", "\(gccIncludePrefix)/include-fixed",
        "-Xcc", "-I", "-Xcc", "\(gccIncludePrefix)/../../../../arm-none-eabi/include",
        "-I", "\(playdateSDKPath)/C_API"
    ]),
]}
var gccIncludePrefix: String {
    "/usr/local/playdate/gcc-arm-none-eabi-9-2019-q4-major/lib/gcc/arm-none-eabi/9.2.1"
}
var playdateSDKPath: String {
    if let path = Context.environment["PLAYDATE_SDK_PATH"] {
        return path
    }
    return "\(Context.environment["HOME"]!)/Developer/PlaydateSDK/"
}

[STREGA]

PR submitted for the template finnvoor/PlaydateKitTemplate#3