diff --git a/src/Package/Artifact/llvm_compiler_rt.php b/src/Package/Artifact/llvm_compiler_rt.php
index 166500b9..f39893da 100644
--- a/src/Package/Artifact/llvm_compiler_rt.php
+++ b/src/Package/Artifact/llvm_compiler_rt.php
@@ -73,7 +73,7 @@ class llvm_compiler_rt
     {
         $sourceDir ??= SOURCE_PATH . '/llvm-compiler-rt';
         $triple ??= SystemTarget::getCanonicalTriple();
-        $libDir = PKG_ROOT_PATH . '/zig/lib/' . $triple;
+        $libDir = zig::path() . '/lib/' . $triple;
         if ($this->isBuilt($libDir)) {
             return;
         }
@@ -101,7 +101,10 @@ class llvm_compiler_rt
 
     private function detectZigLlvmVersion(): ?string
     {
-        [$rc, $out] = shell()->execWithResult('zig cc --version', false);
+        if (!zig::isInstalled()) {
+            return null;
+        }
+        [$rc, $out] = shell()->execWithResult(escapeshellarg(zig::binary()) . ' cc --version', false);
         if ($rc !== 0) {
             return null;
         }
diff --git a/src/Package/Artifact/llvm_tools.php b/src/Package/Artifact/llvm_tools.php
index 3be55a93..4a64cbbd 100644
--- a/src/Package/Artifact/llvm_tools.php
+++ b/src/Package/Artifact/llvm_tools.php
@@ -102,8 +102,8 @@ class llvm_tools
             '-DLLVM_BUILD_LLVM_DYLIB=OFF',
             '-DLLVM_LINK_LLVM_DYLIB=OFF',
             '-DBUILD_SHARED_LIBS=OFF',
-            '-DCMAKE_C_COMPILER=' . PKG_ROOT_PATH . '/zig/zig-cc',
-            '-DCMAKE_CXX_COMPILER=' . PKG_ROOT_PATH . '/zig/zig-c++',
+            '-DCMAKE_C_COMPILER=' . zig::binary('zig-cc'),
+            '-DCMAKE_CXX_COMPILER=' . zig::binary('zig-c++'),
             '-DCMAKE_INSTALL_PREFIX=' . $installDir,
         ]));
         $jobs = ApplicationContext::get(PackageBuilder::class)->concurrency;
@@ -137,11 +137,10 @@ class llvm_tools
 
     private function detectLlvmVersion(): ?string
     {
-        $zig = PKG_ROOT_PATH . '/zig/zig';
-        if (!is_file($zig)) {
+        if (!zig::isInstalled()) {
             return null;
         }
-        [$rc, $out] = shell()->execWithResult(escapeshellarg($zig) . ' cc --version', false);
+        [$rc, $out] = shell()->execWithResult(escapeshellarg(zig::binary()) . ' cc --version', false);
         if ($rc !== 0) {
             return null;
         }
diff --git a/src/Package/Artifact/zig.php b/src/Package/Artifact/zig.php
index 04ae0b1c..123139d9 100644
--- a/src/Package/Artifact/zig.php
+++ b/src/Package/Artifact/zig.php
@@ -15,6 +15,23 @@ use StaticPHP\Runtime\SystemTarget;
 
 class zig
 {
+    /** Directory zig extracts into. */
+    public static function path(): string
+    {
+        return PKG_ROOT_PATH . '/zig';
+    }
+
+    /** Path to a binary inside the zig install dir (zig, zig-cc, zig-c++, zig-ar, …). */
+    public static function binary(string $name = 'zig'): string
+    {
+        return self::path() . '/' . $name;
+    }
+
+    public static function isInstalled(): bool
+    {
+        return is_file(self::binary());
+    }
+
     #[CustomBinary('zig', [
         'linux-x86_64',
         'linux-aarch64',
diff --git a/src/StaticPHP/Doctor/Item/LlvmCompilerRtCheck.php b/src/StaticPHP/Doctor/Item/LlvmCompilerRtCheck.php
index 368e0267..72f172b8 100644
--- a/src/StaticPHP/Doctor/Item/LlvmCompilerRtCheck.php
+++ b/src/StaticPHP/Doctor/Item/LlvmCompilerRtCheck.php
@@ -5,6 +5,7 @@ declare(strict_types=1);
 namespace StaticPHP\Doctor\Item;
 
 use Package\Artifact\llvm_compiler_rt;
+use Package\Artifact\zig;
 use StaticPHP\Attribute\Doctor\CheckItem;
 use StaticPHP\Attribute\Doctor\FixItem;
 use StaticPHP\Attribute\Doctor\OptionalCheck;
@@ -27,7 +28,7 @@ class LlvmCompilerRtCheck
     #[CheckItem('if llvm-compiler-rt is built for current target', level: 799)]
     public function checkLlvmCompilerRt(): CheckResult
     {
-        $libDir = PKG_ROOT_PATH . '/zig/lib/' . SystemTarget::getCanonicalTriple();
+        $libDir = zig::dir() . '/lib/' . SystemTarget::getCanonicalTriple();
         if (new llvm_compiler_rt()->isBuilt($libDir)) {
             return CheckResult::ok($libDir);
         }
@@ -41,7 +42,7 @@ class LlvmCompilerRtCheck
         $installer->addInstallPackage('llvm-compiler-rt');
         $installer->run(true);
         new llvm_compiler_rt()->buildForTriple();
-        $libDir = PKG_ROOT_PATH . '/zig/lib/' . SystemTarget::getCanonicalTriple();
+        $libDir = zig::dir() . '/lib/' . SystemTarget::getCanonicalTriple();
         return new llvm_compiler_rt()->isBuilt($libDir);
     }
 }
diff --git a/src/StaticPHP/Doctor/Item/ZigCheck.php b/src/StaticPHP/Doctor/Item/ZigCheck.php
index ec140fd7..0f84263c 100644
--- a/src/StaticPHP/Doctor/Item/ZigCheck.php
+++ b/src/StaticPHP/Doctor/Item/ZigCheck.php
@@ -4,6 +4,7 @@ declare(strict_types=1);
 
 namespace StaticPHP\Doctor\Item;
 
+use Package\Artifact\zig;
 use StaticPHP\Attribute\Doctor\CheckItem;
 use StaticPHP\Attribute\Doctor\FixItem;
 use StaticPHP\Attribute\Doctor\OptionalCheck;
@@ -26,7 +27,7 @@ class ZigCheck
     public function checkZig(): CheckResult
     {
         if (new PackageInstaller()->addInstallPackage('zig')->isPackageInstalled('zig')) {
-            return CheckResult::ok(PKG_ROOT_PATH . '/zig/zig');
+            return CheckResult::ok(zig::binary());
         }
         return CheckResult::fail('zig is not installed', 'install-zig');
     }
diff --git a/src/StaticPHP/Runtime/SystemTarget.php b/src/StaticPHP/Runtime/SystemTarget.php
index b968dee8..3949443b 100644
--- a/src/StaticPHP/Runtime/SystemTarget.php
+++ b/src/StaticPHP/Runtime/SystemTarget.php
@@ -4,6 +4,7 @@ declare(strict_types=1);
 
 namespace StaticPHP\Runtime;
 
+use StaticPHP\Toolchain\ZigToolchain;
 use StaticPHP\Util\System\LinuxUtil;
 
 /**
@@ -16,7 +17,7 @@ class SystemTarget
      */
     public static function getLibc(): ?string
     {
-        if ($target = getenv('SPC_TARGET')) {
+        if ($target = self::target()) {
             if (str_contains($target, '-gnu')) {
                 return 'glibc';
             }
@@ -57,7 +58,7 @@ class SystemTarget
     public static function getLibcVersion(): ?string
     {
         if (PHP_OS_FAMILY === 'Linux') {
-            $target = (string) getenv('SPC_TARGET');
+            $target = self::target();
             if (str_contains($target, '-gnu.2.')) {
                 return preg_match('/-gnu\.(2\.\d+)/', $target, $matches) ? $matches[1] : null;
             }
@@ -75,7 +76,7 @@ class SystemTarget
      */
     public static function getTargetOS(): string
     {
-        $target = (string) getenv('SPC_TARGET');
+        $target = self::target();
         return match (true) {
             str_contains($target, '-linux') => 'Linux',
             str_contains($target, '-macos') => 'Darwin',
@@ -91,7 +92,7 @@ class SystemTarget
      */
     public static function getTargetArch(): string
     {
-        $target = (string) getenv('SPC_TARGET');
+        $target = self::target();
         return match (true) {
             str_contains($target, 'x86_64') || str_contains($target, 'amd64') => 'x86_64',
             str_contains($target, 'aarch64') || str_contains($target, 'arm64') => 'aarch64',
@@ -136,7 +137,7 @@ class SystemTarget
      */
     public static function getCanonicalTriple(): string
     {
-        $target = (string) getenv('SPC_TARGET');
+        $target = self::target();
         if ($target !== '' && !str_contains($target, 'native')) {
             $cleaned = (string) preg_replace('/(-gnu|-musl)\.[\d.]+/', '$1', $target);
             $cleaned = preg_split('/\s+/', trim($cleaned))[0] ?? '';
@@ -161,7 +162,7 @@ class SystemTarget
      */
     public static function getAutoconfHostTriple(): ?string
     {
-        $target = (string) getenv('SPC_TARGET');
+        $target = self::target();
         if ($target === '' || str_contains($target, 'native')) {
             return null;
         }
@@ -183,4 +184,14 @@ class SystemTarget
         }
         return $cleaned;
     }
+
+    /** native toolchains ignore SPC_TARGET */
+    private static function target(): string
+    {
+        $tc = (string) getenv('SPC_TOOLCHAIN');
+        if ($tc !== '' && $tc !== ZigToolchain::class) {
+            return '';
+        }
+        return (string) getenv('SPC_TARGET');
+    }
 }
diff --git a/src/StaticPHP/Toolchain/ZigToolchain.php b/src/StaticPHP/Toolchain/ZigToolchain.php
index 7058a845..05819b16 100644
--- a/src/StaticPHP/Toolchain/ZigToolchain.php
+++ b/src/StaticPHP/Toolchain/ZigToolchain.php
@@ -5,6 +5,7 @@ declare(strict_types=1);
 namespace StaticPHP\Toolchain;
 
 use Package\Artifact\llvm_compiler_rt;
+use Package\Artifact\zig;
 use StaticPHP\DI\ApplicationContext;
 use StaticPHP\Package\PackageBuilder;
 use StaticPHP\Package\PackageInstaller;
@@ -56,7 +57,7 @@ class ZigToolchain implements UnixToolchainInterface
         GlobalEnvManager::putenv("SPC_DEFAULT_CXXFLAGS={$cxxflags}");
         GlobalEnvManager::putenv("SPC_CMD_VAR_PHP_MAKE_EXTRA_CFLAGS={$extraCflags}");
         GlobalEnvManager::putenv('RANLIB=zig-ranlib');
-        GlobalEnvManager::putenv('SPC_COMPILER_RT_DIR=' . PKG_ROOT_PATH . '/zig/lib/' . SystemTarget::getCanonicalTriple());
+        GlobalEnvManager::putenv('SPC_COMPILER_RT_DIR=' . zig::path() . '/lib/' . SystemTarget::getCanonicalTriple());
         GlobalEnvManager::putenv('OBJCOPY=' . PKG_ROOT_PATH . '/llvm-tools/bin/llvm-objcopy');
         $extra_libs = getenv('SPC_EXTRA_LIBS') ?: '';
         if (!str_contains($extra_libs, '-lunwind')) {
@@ -112,9 +113,12 @@ class ZigToolchain implements UnixToolchainInterface
 
     private function ensureCompilerRt(): void
     {
+        if (!zig::isInstalled()) {
+            return;
+        }
         $rt = new llvm_compiler_rt();
         $triple = SystemTarget::getCanonicalTriple();
-        $libDir = PKG_ROOT_PATH . '/zig/lib/' . $triple;
+        $libDir = zig::path() . '/lib/' . $triple;
         if ($rt->isBuilt($libDir)) {
             return;
         }
@@ -154,6 +158,6 @@ class ZigToolchain implements UnixToolchainInterface
 
     private function getPath(): string
     {
-        return PKG_ROOT_PATH . '/zig';
+        return zig::path();
     }
 }
diff --git a/src/StaticPHP/Util/GlobalEnvManager.php b/src/StaticPHP/Util/GlobalEnvManager.php
index 5b4b16b2..eb44112e 100644
--- a/src/StaticPHP/Util/GlobalEnvManager.php
+++ b/src/StaticPHP/Util/GlobalEnvManager.php
@@ -123,6 +123,24 @@ class GlobalEnvManager
         }
     }
 
+    /** Re-substitute env.ini's CC=${SPC_DEFAULT_CC} bindings after a toolchain swap. */
+    public static function reapplyOsIni(): void
+    {
+        $ini = self::readIniFile();
+        $os_ini = match (PHP_OS_FAMILY) {
+            'Windows' => $ini['windows'] ?? [],
+            'Darwin' => $ini['macos'] ?? [],
+            'Linux' => $ini['linux'] ?? [],
+            'BSD' => $ini['freebsd'] ?? [],
+            default => [],
+        };
+        foreach (['CC', 'CXX', 'AR', 'RANLIB', 'LD'] as $k) {
+            if (isset($os_ini[$k])) {
+                self::putenv("{$k}={$os_ini[$k]}");
+            }
+        }
+    }
+
     /**
      * Initialize the toolchain after the environment variables are set.
      * The toolchain or environment availability check is done here.