add system include paths and add include paths to c-translated modules

examples/sdl2/third-party/sdl2/build.zig

@@ -170,10 +170,7 @@ pub fn build(b: *std.Build) !void {
     b.installArtifact(lib);
 
     var sdl_c_module = b.addTranslateC(.{
-        // NOTE(jae): 2025-03-13
-        // Using host target platform to avoid include errors when targetting Android
-        // Otherwise we get errors like: 'sys/types.h' file not found
-        .target = b.graph.host,
+        .target = target,
         .optimize = .ReleaseFast,
         .root_source_file = b.path("src/sdl.h"),
     });

src/androidbuild/apk.zig

@@ -412,6 +412,29 @@ fn doInstallApk(apk: *Apk) std.mem.Allocator.Error!*Step.InstallFile {
             }
         }
 
+        // Find TranslateC dependencies and add system path
+        var iter = artifact.root_module.import_table.iterator();
+        while (iter.next()) |it| {
+            const module = it.value_ptr.*;
+            const root_source_file = module.root_source_file orelse continue;
+            switch (root_source_file) {
+                .generated => |gen| {
+                    const step = gen.file.step;
+                    if (step.id != .translate_c) {
+                        continue;
+                    }
+                    const c_translate_target = module.resolved_target orelse continue;
+                    if (!c_translate_target.result.abi.isAndroid()) {
+                        continue;
+                    }
+                    const translate_c: *std.Build.Step.TranslateC = @fieldParentPtr("step", step);
+                    translate_c.addIncludePath(.{ .cwd_relative = apk.tools.include_path });
+                    translate_c.addSystemIncludePath(.{ .cwd_relative = apk.tools.getSystemIncludePath(c_translate_target) });
+                },
+                else => continue,
+            }
+        }
+
         // update linked libraries that use C or C++ to:
         // - use Android LibC file
         // - add Android NDK library paths. (libandroid, liblog, etc)

src/androidbuild/tools.zig

@@ -28,6 +28,8 @@ api_level: APILevel,
 ndk_version: []const u8,
 /// ie. "$ANDROID_HOME/ndk/{ndk_version}/toolchains/llvm/prebuilt/{host_os_and_arch}/sysroot"
 ndk_sysroot_path: []const u8,
+/// ie. "$ANDROID_HOME/ndk/{ndk_version}/toolchains/llvm/prebuilt/{host_os_and_arch}/sysroot/usr/include"
+include_path: []const u8,
 /// ie. "$ANDROID_HOME/Sdk/platforms/android-{api_level}/android.jar"
 root_jar: []const u8,
 // $JDK_HOME, $JAVA_HOME or auto-discovered from java binaries found in $PATH
@@ -320,6 +322,7 @@ pub fn create(b: *std.Build, options: Options) *Tools {
         .api_level = options.api_level,
         .ndk_version = options.ndk_version,
         .ndk_sysroot_path = android_ndk_sysroot,
+        .include_path = b.fmt("{s}/usr/include", .{tools.ndk_sysroot_path}),
         .root_jar = root_jar,
         .jdk_path = jdk_path,
         .build_tools = .{
@@ -439,9 +442,7 @@ pub fn createKeyStore(tools: *const Tools, options: CreateKey) KeyStore {
 pub fn setLibCFile(tools: *const Tools, compile: *Step.Compile) void {
     const b = tools.b;
 
-    const target: ResolvedTarget = compile.root_module.resolved_target orelse {
-        @panic(b.fmt("no 'target' set on Android module", .{}));
-    };
+    const target: ResolvedTarget = compile.root_module.resolved_target orelse @panic("no 'target' set on Android module");
     const system_target = getAndroidTriple(target) catch |err| @panic(@errorName(err));
 
     const android_libc_path = createLibC(
@@ -455,6 +456,12 @@ pub fn setLibCFile(tools: *const Tools, compile: *Step.Compile) void {
     compile.setLibCFile(android_libc_path);
 }
 
+pub fn getSystemIncludePath(tools: *const Tools, target: ResolvedTarget) []const u8 {
+    const b = tools.b;
+    const system_target = getAndroidTriple(target) catch |err| @panic(@errorName(err));
+    return b.fmt("{s}/{s}", .{ tools.include_path, system_target });
+}
+
 fn createLibC(b: *std.Build, system_target: []const u8, android_version: APILevel, ndk_sysroot_path: []const u8, ndk_version: []const u8) LazyPath {
     const libc_file_format =
         \\# Generated by zig-android-sdk. DO NOT EDIT.