Tests cross compilation in CI, workaround for xscrnsaver hash depending on platform

Author: MasonRemaley

.github/workflows/ci.yaml

@@ -33,5 +33,8 @@ jobs:
         if: runner.os != 'Windows' # zig fmt failing on Windows CI, unclear why
         run: zig fmt --ast-check --check .
 
-      - name: Build
-        run: zig build --summary all
+      - name: Build for Windows
+        run: zig build -Dtarget=x86_64-windows-gnu --summary all
+
+      - name: Build for Linux
+        run: zig build -Dtarget=x86_64-linux-gnu --summary all

build.zig.zon

@@ -72,10 +72,6 @@
             .url = "https://gitlab.freedesktop.org/xorg/lib/libxrender/-/archive/libXrender-0.9.12/libxrender-libXrender-0.9.12.tar.gz",
             .hash = "N-V-__8AANorBADbt-RlITZJofNvQWTiaQlv7r7lWYtxAqGx",
         },
-        .xscrnsaver = .{
-            .url = "https://gitlab.freedesktop.org/xorg/lib/libxscrnsaver/-/archive/libXScrnSaver-1.2.4/libxscrnsaver-libXScrnSaver-1.2.4.tar.gz",
-            .hash = "N-V-__8AAMXRAAAKIBB3YHvwcykG71lH-HtylfJ0AV048a7V",
-        },
         .decor = .{
             .url = "https://gitlab.freedesktop.org/libdecor/libdecor/-/archive/0.2.3/libdecor-0.2.3.tar.gz",
             .hash = "N-V-__8AAEG5BAAsZkN2QXLyeuqTnHEOXHHUOGPC9azQ7zq8",
@@ -116,6 +112,19 @@
             .hash = "N-V-__8AAH-J2wA1QFgeIKK0hLveAjq3mNnOJb96xak4HFqx",
             .lazy = true,
         },
+        .xscrnsaver = .{
+            // This dependency must be kept in sync with `xscrnsaver_windows` for similar reasons explained in the `pulseaudio` dependency.
+            .url = "https://gitlab.freedesktop.org/xorg/lib/libxscrnsaver/-/archive/libXScrnSaver-1.2.4/libxscrnsaver-libXScrnSaver-1.2.4.tar.gz",
+            .hash = "N-V-__8AAMXRAAAKIBB3YHvwcykG71lH-HtylfJ0AV048a7V",
+            .lazy = true,
+        },
+        .xscrnsaver_windows = .{
+            // This is a duplicate of `xscrnsaver`, but with a different hash due to a Zig bug that
+            // results in a different hash on Windows than Linux.
+            .url = "https://gitlab.freedesktop.org/xorg/lib/libxscrnsaver/-/archive/libXScrnSaver-1.2.4/libxscrnsaver-libXScrnSaver-1.2.4.tar.gz",
+            .hash = "N-V-__8AAEO3AADhS3i2HiVniZnPqWJh33VqmmUp7JO33xqe",
+            .lazy = true,
+        },
         .alsa = .{
             .url = "https://github.com/alsa-project/alsa-lib/archive/refs/tags/v1.2.14.tar.gz",
             .hash = "N-V-__8AACPMQgBfqlZq9Kx2qUwCMrZVkl-5dDd5bVDiF06E",

src/linux.zig

@@ -436,6 +436,16 @@ pub fn build(
             lib.addIncludePath(b.path("deps/alsa/include"));
         }
 
+        // Provide the xscrnsaver headers. Conditional is workaround for cross compilation, see
+        // comment in `build.zig.zon`
+        const xscrnsaver_name = switch (@import("builtin").os.tag) {
+            .windows => "xscrnsaver_windows",
+            else => "xscrnsaver",
+        };
+        if (b.lazyDependency(xscrnsaver_name, .{})) |xscrnsaver| {
+            lib.addIncludePath(xscrnsaver.path("include"));
+        }
+
         // Provide upstream headers that don't require any special handling
         lib.addIncludePath(b.dependency("egl", .{}).path("api"));
         lib.addIncludePath(b.dependency("opengl", .{}).path("api"));
@@ -447,7 +457,6 @@ pub fn build(
         lib.addIncludePath(b.dependency("xfixes", .{}).path("include"));
         lib.addIncludePath(b.dependency("xrandr", .{}).path("include"));
         lib.addIncludePath(b.dependency("xrender", .{}).path("include"));
-        lib.addIncludePath(b.dependency("xscrnsaver", .{}).path("include"));
         lib.addIncludePath(b.dependency("jack", .{}).path("common"));
         lib.addIncludePath(b.dependency("sndio", .{}).path("libsndio"));
         lib.addIncludePath(b.path("deps/wayland/protocols"));