diff --git a/Makefile b/Makefile
index 0ca915b9..a88cff4e 100644
--- a/Makefile
+++ b/Makefile
@@ -4,6 +4,25 @@
 ZIG := zig
 BC := $(dir $(abspath $(lastword $(MAKEFILE_LIST))))
 
+# OS and ARCH
+kernel = $(shell uname -ms)
+ifeq ($(kernel), Darwin arm64)
+	OS := macos
+	ARCH := aarch64
+else ifeq ($(kernel), Linux aarch64)
+	OS := linux
+	ARCH := aarch64
+else ifeq ($(kernel), Linux arm64)
+	OS := linux
+	ARCH := aarch64
+else ifeq ($(kernel), Linux x86_64)
+	OS := linux
+	ARCH := x86_64
+else
+	$(error "Unhandled kernel: $(kernel)")
+endif
+
+
 # Infos
 # -----
 .PHONY: help
@@ -26,30 +45,11 @@ help:
 .PHONY: build build-dev run run-release shell test bench download-zig wpt
 
 zig_version = $(shell grep 'recommended_zig_version = "' "vendor/zig-js-runtime/build.zig" | cut -d'"' -f2)
-kernel = $(shell uname -ms)
 
 ## Download the zig recommended version
 download-zig:
-ifeq ($(kernel), Darwin x86_64)
-	$(eval target="macos")
-	$(eval arch="x86_64")
-else ifeq ($(kernel), Darwin arm64)
-	$(eval target="macos")
-	$(eval arch="aarch64")
-else ifeq ($(kernel), Linux aarch64)
-	$(eval target="linux")
-	$(eval arch="aarch64")
-else ifeq ($(kernel), Linux arm64)
-	$(eval target="linux")
-	$(eval arch="aarch64")
-else ifeq ($(kernel), Linux x86_64)
-	$(eval target="linux")
-	$(eval arch="x86_64")
-else
-	$(error "Unhandled kernel: $(kernel)")
-endif
-	$(eval url = "https://ziglang.org/builds/zig-$(target)-$(arch)-$(zig_version).tar.xz")
-	$(eval dest = "/tmp/zig-$(target)-$(arch)-$(zig_version).tar.xz")
+	$(eval url = "https://ziglang.org/builds/zig-$(OS)-$(ARCH)-$(zig_version).tar.xz")
+	$(eval dest = "/tmp/zig-$(OS)-$(ARCH)-$(zig_version).tar.xz")
 	@printf "\e[36mDownload zig version $(zig_version)...\e[0m\n"
 	@curl -o "$(dest)" -L "$(url)" || (printf "\e[33mBuild ERROR\e[0m\n"; exit 1;)
 	@printf "\e[33mDownloaded $(dest)\e[0m\n"
@@ -188,24 +188,27 @@ install-zig-js-runtime:
 	make install
 
 .PHONY: _build_mimalloc
-_build_mimalloc:
-	@cd vendor/mimalloc && \
-		mkdir -p out/include && \
-		cp include/mimalloc.h out/include/ && \
-		cd out && \
-		cmake -DMI_BUILD_SHARED=OFF -DMI_BUILD_OBJECT=OFF -DMI_BUILD_TESTS=OFF -DMI_OVERRIDE=OFF $(OPTS) .. && \
-		make
+MIMALLOC := $(BC)vendor/mimalloc/out/$(OS)-$(ARCH)
+_build_mimalloc: clean-mimalloc
+	@mkdir -p $(MIMALLOC)/build && \
+	cd $(MIMALLOC)/build && \
+	cmake -DMI_BUILD_SHARED=OFF -DMI_BUILD_OBJECT=OFF -DMI_BUILD_TESTS=OFF -DMI_OVERRIDE=OFF $(OPTS) ../../.. && \
+	make && \
+	mkdir -p $(MIMALLOC)/lib
 
 install-mimalloc-dev: _build_mimalloc
 install-mimalloc-dev: OPTS=-DCMAKE_BUILD_TYPE=Debug
 install-mimalloc-dev:
-	@cd vendor/mimalloc/out && \
-		mv libmimalloc-debug.a libmimalloc.a
+	@cd $(MIMALLOC) && \
+	mv build/libmimalloc-debug.a lib/libmimalloc.a
 
 install-mimalloc: _build_mimalloc
+install-mimalloc:
+	@cd $(MIMALLOC) && \
+	mv build/libmimalloc.a lib/libmimalloc.a
 
 clean-mimalloc:
-	@rm -fr vendor/mimalloc/lib/*
+	@rm -Rf $(MIMALLOC)/build
 
 ## Init and update git submodule
 install-submodule:
diff --git a/build.zig b/build.zig
index 364c24cf..9b356412 100644
--- a/build.zig
+++ b/build.zig
@@ -146,15 +146,16 @@ fn common(
     step: *std.Build.Step.Compile,
     options: jsruntime.Options,
 ) !void {
+    const target = step.root_module.resolved_target.?;
     const jsruntimemod = try jsruntime_pkgs.module(
         b,
         options,
         step.root_module.optimize.?,
-        step.root_module.resolved_target.?,
+        target,
     );
     step.root_module.addImport("jsruntime", jsruntimemod);
 
-    const netsurf = moduleNetSurf(b);
+    const netsurf = try moduleNetSurf(b, target);
     netsurf.addImport("jsruntime", jsruntimemod);
     step.root_module.addImport("netsurf", netsurf);
 
@@ -164,16 +165,17 @@ fn common(
     step.root_module.addImport("tls", tlsmod);
 }
 
-fn moduleNetSurf(b: *std.Build) *std.Build.Module {
+fn moduleNetSurf(b: *std.Build, target: std.Build.ResolvedTarget) !*std.Build.Module {
     const mod = b.addModule("netsurf", .{
         .root_source_file = b.path("src/netsurf/netsurf.zig"),
+        .target = target,
     });
     // iconv
     mod.addObjectFile(b.path("vendor/libiconv/lib/libiconv.a"));
     mod.addIncludePath(b.path("vendor/libiconv/include"));
 
     // mimalloc
-    mod.addImport("mimalloc", moduleMimalloc(b));
+    mod.addImport("mimalloc", (try moduleMimalloc(b, target)));
 
     // netsurf libs
     const ns = "vendor/netsurf";
@@ -193,13 +195,23 @@ fn moduleNetSurf(b: *std.Build) *std.Build.Module {
     return mod;
 }
 
-fn moduleMimalloc(b: *std.Build) *std.Build.Module {
+fn moduleMimalloc(b: *std.Build, target: std.Build.ResolvedTarget) !*std.Build.Module {
     const mod = b.addModule("mimalloc", .{
         .root_source_file = b.path("src/mimalloc/mimalloc.zig"),
+        .target = target,
     });
 
-    mod.addObjectFile(b.path("vendor/mimalloc/out/libmimalloc.a"));
-    mod.addIncludePath(b.path("vendor/mimalloc/out/include"));
+    const os = target.result.os.tag;
+    const arch = target.result.cpu.arch;
+
+    const mimalloc = "vendor/mimalloc";
+    const lib_path = try std.fmt.allocPrint(
+        mod.owner.allocator,
+        mimalloc ++ "/out/{s}-{s}/lib/libmimalloc.a",
+        .{ @tagName(os), @tagName(arch) },
+    );
+    mod.addObjectFile(b.path(lib_path));
+    mod.addIncludePath(b.path(mimalloc ++ "/include"));
 
     return mod;
 }