diff --git a/.php-cs-fixer.php b/.php-cs-fixer.php
index 47d17866..6e57f183 100644
--- a/.php-cs-fixer.php
+++ b/.php-cs-fixer.php
@@ -69,4 +69,5 @@ return (new PhpCsFixer\Config())
     ])
     ->setFinder(
         PhpCsFixer\Finder::create()->in([__DIR__ . '/src', __DIR__ . '/tests/SPC'])
-    );
+    )
+    ->setParallelConfig(PhpCsFixer\Runner\Parallel\ParallelConfigFactory::detect());
diff --git a/src/SPC/builder/linux/LinuxBuilder.php b/src/SPC/builder/linux/LinuxBuilder.php
index 7ff6cff7..31a9cd5a 100644
--- a/src/SPC/builder/linux/LinuxBuilder.php
+++ b/src/SPC/builder/linux/LinuxBuilder.php
@@ -13,6 +13,7 @@ use SPC\store\SourcePatcher;
 use SPC\toolchain\ToolchainManager;
 use SPC\toolchain\ZigToolchain;
 use SPC\util\GlobalEnvManager;
+use SPC\util\SPCTarget;
 
 class LinuxBuilder extends UnixBuilderBase
 {
@@ -92,7 +93,9 @@ class LinuxBuilder extends UnixBuilderBase
             $zts = '';
         }
         $disable_jit = $this->getOption('disable-opcache-jit', false) ? '--disable-opcache-jit ' : '';
-
+        if (!$disable_jit && $this->getExt('opcache')) {
+            f_putenv('COMPILER_EXTRA=-fno-sanitize=undefined');
+        }
         $config_file_path = $this->getOption('with-config-file-path', false) ?
             ('--with-config-file-path=' . $this->getOption('with-config-file-path') . ' ') : '';
         $config_file_scan_dir = $this->getOption('with-config-file-scan-dir', false) ?
@@ -123,6 +126,12 @@ class LinuxBuilder extends UnixBuilderBase
         }
 
         $embed_type = getenv('SPC_CMD_VAR_PHP_EMBED_TYPE') ?: 'static';
+        if ($embed_type !== 'static' && SPCTarget::isStatic()) {
+            throw new WrongUsageException(
+                'Linux does not support loading shared libraries when linking libc statically. ' .
+                'Change SPC_CMD_VAR_PHP_EMBED_TYPE to static.'
+            );
+        }
         shell()->cd(SOURCE_PATH . '/php-src')
             ->exec(
                 getenv('SPC_CMD_PREFIX_PHP_CONFIGURE') . ' ' .
diff --git a/src/SPC/builder/unix/library/libaom.php b/src/SPC/builder/unix/library/libaom.php
index 31c40a0f..9c10079b 100644
--- a/src/SPC/builder/unix/library/libaom.php
+++ b/src/SPC/builder/unix/library/libaom.php
@@ -4,28 +4,24 @@ declare(strict_types=1);
 
 namespace SPC\builder\unix\library;
 
-use SPC\exception\FileSystemException;
-use SPC\exception\RuntimeException;
 use SPC\toolchain\ToolchainManager;
 use SPC\toolchain\ZigToolchain;
 use SPC\util\executor\UnixCMakeExecutor;
 
 trait libaom
 {
-    /**
-     * @throws RuntimeException
-     * @throws FileSystemException
-     */
     protected function build(): void
     {
+        $extra = getenv('COMPILER_EXTRA');
         if (ToolchainManager::getToolchainClass() === ZigToolchain::class) {
-            f_putenv('COMPILER_EXTRA=-D_GNU_SOURCE');
+            $new = trim($extra . ' -D_GNU_SOURCE');
+            f_putenv("COMPILER_EXTRA={$new}");
         }
         UnixCMakeExecutor::create($this)
             ->setBuildDir("{$this->source_dir}/builddir")
             ->addConfigureArgs('-DAOM_TARGET_CPU=generic')
             ->build();
-        f_putenv('COMPILER_EXTRA');
+        f_putenv("COMPILER_EXTRA={$extra}");
         $this->patchPkgconfPrefix(['aom.pc']);
     }
 }