sysroot: user-sysroot or package-sysroot (no error on wasm)

build.zig

@@ -216,12 +216,6 @@ fn buildExample(b: *Builder, target: CrossTarget, optimize: OptimizeMode, sokol:
 pub fn build(b: *Builder) !void {
     var options: LibSokolOptions = .{};
 
-    options.package = b.dependency("emsdk", .{});
-    if (b.sysroot) |sysroot|
-        options.sysroot = sysroot
-    else
-        options.sysroot = b.pathJoin(&.{ options.packagePath(b), "upstream", "emscripten", "cache", "sysroot" });
-
     const force_gl = b.option(bool, "gl", "Force GL backend") orelse false;
     options.backend = if (force_gl) .gl else .auto;
 
@@ -234,6 +228,13 @@ pub fn build(b: *Builder) !void {
     const target = b.standardTargetOptions(.{});
     const optimize = b.standardOptimizeOption(.{});
     options.optimize = optimize;
+    if (target.result.isWasm()) {
+        options.package = b.dependency("emsdk", .{});
+        if (b.sysroot) |sysroot|
+            options.sysroot = sysroot
+        else
+            options.sysroot = b.pathJoin(&.{ options.packagePath(b), "upstream", "emscripten", "cache", "sysroot" });
+    }
     const sokol = buildSokol(b, target, optimize, options, "");
 
     const examples = .{