diff --git a/src/SPC/builder/Extension.php b/src/SPC/builder/Extension.php
index 50d8837a..ba4ddefe 100644
--- a/src/SPC/builder/Extension.php
+++ b/src/SPC/builder/Extension.php
@@ -405,7 +405,7 @@ class Extension
             'LDFLAGS' => $config['ldflags'],
             'LIBS' => $preStatic . $staticLibString . $postStatic . $sharedLibString,
             'LD_LIBRARY_PATH' => BUILD_LIB_PATH,
-            'COMPILER_EXTRA' => '-lstdc++',
+            'SPC_COMPILER_EXTRA' => '-lstdc++',
         ];
 
         if ($this->patchBeforeSharedPhpize()) {
diff --git a/src/SPC/builder/linux/LinuxBuilder.php b/src/SPC/builder/linux/LinuxBuilder.php
index 9f9fd018..be856a65 100644
--- a/src/SPC/builder/linux/LinuxBuilder.php
+++ b/src/SPC/builder/linux/LinuxBuilder.php
@@ -32,7 +32,7 @@ class LinuxBuilder extends UnixBuilderBase
         GlobalEnvManager::afterInit();
 
         // concurrency
-        $this->concurrency = intval(getenv('SPC_CONCURRENCY'));
+        $this->concurrency = (int) getenv('SPC_CONCURRENCY');
         // cflags
         $this->arch_c_flags = getenv('SPC_DEFAULT_C_FLAGS');
         $this->arch_cxx_flags = getenv('SPC_DEFAULT_CXX_FLAGS');
@@ -94,7 +94,7 @@ class LinuxBuilder extends UnixBuilderBase
         }
         $disable_jit = $this->getOption('disable-opcache-jit', false) ? '--disable-opcache-jit ' : '';
         if (!$disable_jit && $this->getExt('opcache')) {
-            f_putenv('COMPILER_EXTRA=-fno-sanitize=undefined');
+            f_putenv('SPC_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') . ' ') : '';
diff --git a/src/SPC/builder/macos/MacOSBuilder.php b/src/SPC/builder/macos/MacOSBuilder.php
index 329d09e0..f6e1fb64 100644
--- a/src/SPC/builder/macos/MacOSBuilder.php
+++ b/src/SPC/builder/macos/MacOSBuilder.php
@@ -34,7 +34,7 @@ class MacOSBuilder extends UnixBuilderBase
 
         // ---------- set necessary compile vars ----------
         // concurrency
-        $this->concurrency = intval(getenv('SPC_CONCURRENCY'));
+        $this->concurrency = (int) getenv('SPC_CONCURRENCY');
         // cflags
         $this->arch_c_flags = getenv('SPC_DEFAULT_C_FLAGS');
         $this->arch_cxx_flags = getenv('SPC_DEFAULT_CXX_FLAGS');
diff --git a/src/SPC/builder/unix/library/libaom.php b/src/SPC/builder/unix/library/libaom.php
index 9c10079b..f2f50d85 100644
--- a/src/SPC/builder/unix/library/libaom.php
+++ b/src/SPC/builder/unix/library/libaom.php
@@ -12,16 +12,16 @@ trait libaom
 {
     protected function build(): void
     {
-        $extra = getenv('COMPILER_EXTRA');
+        $extra = getenv('SPC_COMPILER_EXTRA');
         if (ToolchainManager::getToolchainClass() === ZigToolchain::class) {
             $new = trim($extra . ' -D_GNU_SOURCE');
-            f_putenv("COMPILER_EXTRA={$new}");
+            f_putenv("SPC_COMPILER_EXTRA={$new}");
         }
         UnixCMakeExecutor::create($this)
             ->setBuildDir("{$this->source_dir}/builddir")
             ->addConfigureArgs('-DAOM_TARGET_CPU=generic')
             ->build();
-        f_putenv("COMPILER_EXTRA={$extra}");
+        f_putenv("SPC_COMPILER_EXTRA={$extra}");
         $this->patchPkgconfPrefix(['aom.pc']);
     }
 }
diff --git a/src/SPC/builder/windows/WindowsBuilder.php b/src/SPC/builder/windows/WindowsBuilder.php
index 25a503eb..618d7238 100644
--- a/src/SPC/builder/windows/WindowsBuilder.php
+++ b/src/SPC/builder/windows/WindowsBuilder.php
@@ -45,7 +45,7 @@ class WindowsBuilder extends BuilderBase
         $this->zts = $this->getOption('enable-zts', false);
 
         // set concurrency
-        $this->concurrency = intval(getenv('SPC_CONCURRENCY'));
+        $this->concurrency = (int) getenv('SPC_CONCURRENCY');
 
         // make cmake toolchain
         $this->cmake_toolchain_file = SystemUtil::makeCmakeToolchainFile();
diff --git a/src/SPC/store/scripts/zig-cc.sh b/src/SPC/store/scripts/zig-cc.sh
index 4dd0f6c9..d162a369 100644
--- a/src/SPC/store/scripts/zig-cc.sh
+++ b/src/SPC/store/scripts/zig-cc.sh
@@ -29,7 +29,7 @@ done
 [[ -n "$SPC_TARGET" ]] && TARGET="-target $SPC_TARGET" || TARGET=""
 
 if [[ "$SPC_TARGET" =~ \.[0-9]+\.[0-9]+ ]]; then
-    output=$(zig cc $TARGET $COMPILER_EXTRA "${PARSED_ARGS[@]}" 2>&1)
+    output=$(zig cc $TARGET $SPC_COMPILER_EXTRA "${PARSED_ARGS[@]}" 2>&1)
     status=$?
 
     if [[ $status -eq 0 ]]; then
@@ -44,4 +44,4 @@ if [[ "$SPC_TARGET" =~ \.[0-9]+\.[0-9]+ ]]; then
     fi
 fi
 
-exec zig cc $TARGET $COMPILER_EXTRA "${PARSED_ARGS[@]}"
+exec zig cc $TARGET $SPC_COMPILER_EXTRA "${PARSED_ARGS[@]}"