fix build on linux

build.zig

@@ -855,6 +855,13 @@ fn addSystemSDK(
         try @import("apple_sdk").addPaths(b, step);
     }
 
+    if (step.target.isLinux()) {
+        step.linkLibrary(b.dependency("x11_headers", .{
+            .target = step.target,
+            .optimize = step.optimize,
+        }).artifact("x11-headers"));
+    }
+
     // GLFW requires these on all platforms so we just add them here. It
     // doesn't hurt to add them if we don't use GLFW since they're all
     // namespaced.
@@ -862,10 +869,6 @@ fn addSystemSDK(
         .target = step.target,
         .optimize = step.optimize,
     }).artifact("vulkan-headers"));
-    // step.linkLibrary(b.dependency("x11_headers", .{
-    //     .target = step.target,
-    //     .optimize = step.optimize,
-    // }).artifact("x11-headers"));
 }
 
 fn benchSteps(

build.zig.zon

@@ -42,5 +42,9 @@
             .url = "https://pkg.machengine.org/vulkan-headers/fc495148a910ac7817ce0ec2d5948231806f2ac0.tar.gz",
             .hash = "12209aeba80369fa8638b82179b47e6742adb98a3a5b01bc518565504a922baad3e4",
         },
+        .x11_headers = .{
+            .url = "https://pkg.machengine.org/x11-headers/26d12e9fc0d893085bcb711088a4a19afdff1adc.tar.gz",
+            .hash = "1220371a61d8bb57fce8ee1741f623cc19b0edd7d1b4adc9918663f8a7ef08aa4f3f",
+        },
     },
 }

pkg/fontconfig/build.zig

@@ -165,7 +165,7 @@ pub fn build(b: *std.Build) !void {
     lib.installHeadersDirectoryOptions(.{
         .source_dir = upstream.path("fontconfig"),
         .install_dir = .header,
-        .install_subdir = "",
+        .install_subdir = "fontconfig",
         .include_extensions = &.{".h"},
     });